5.  The applicants, Mr Nizamudin Aliyev (“the first applicant”) and Ms Madina Gadzhiyeva (“the second applicant”), live in Makhachkala, Dagestan. They were born in 1960 and 1987 respectively. The first applicant is the father of Mr Sirazhudin Aliyev, who was born in 1988, and the second applicant is the wife of Mr Gazimagomed Abdullayev, who was born in 1988. 6.  At about 2.30 p.m. on 21 January 2012 Sirazhudin Aliyev and Gazimagomed Abdullayev were driving on an errand in the latter’s VAZ car (the Lada Kalina model) with the registration number E261KP 05 RUS in the centre of Makhachkala, Dagestan, when they were stopped by a group of several armed men in the uniforms of the State Traffic Police (Государственная Инспекция Безопасности Дорожного Движения Министерства внутренних дел Российской Федерации) (hereinafter “the traffic police”), who were driving in a white Toyota and a black VAZ car (the Lada Priora model). The armed men discharged one gunshot, hit Abdullayev’s car with their truncheons, forced Aliyev and Abdullayev out of their car, handcuffed them and placed them separately into their two vehicles and drove away. Shortly thereafter Abdullayev’s car was driven away by the abductors. The abduction took place in the presence of numerous witnesses. 7.  According to the applicants, their relatives were taken to the premises of the Dagestan Centre for Terrorism Counteraction (Центр Противодействия Экстремизму Министерства Внутренних Дел Дагестана) (hereinafter “the CTC”) in Makhachkala. 8.  On 28 January 2012 the flat of the sister of Gazimagomed Abdullayev was searched by police officers from the CTC. 9.  According to the applicants, on 2 February 2012 they learned from sources whose identity they did not disclose that their relatives had been allegedly initially detained on the premises of the CTC in Makhachkala, Dagestan, and then – about two days later – taken to the CTC headquarters in the Stavropol Region. 10.  The Government did not dispute the circumstances of the abduction, as presented by the applicants. However, they denied any involvement of State agents in the incident and pointed out that the applicants had not witnessed the abduction; they also stated that the witness statements concerning the incident were unreliable, and that the allegations of State agents’ involvement had been completely unsubstantiated. 11.  The Court made two requests for copies of the contents of the investigations file. In reply to the Court’s first request, the Government furnished it with copies of documents (numbering 378 pages) reflecting the proceedings between January and August 2012; in reply to the Court’s second request the Government supplied copies of documents (numbering 261 pages) reflecting the proceedings between September 2012 and July 2015. Their contents can be summarised as follows. 12.  On 21 January 2012 the applicants and their relatives complained about the abduction to a number of local law-enforcement agencies, including the Dagestan Public Prosecutor and the investigations department of the Leninskiy district prosecutor’s office in Makhachkala. In their complaints they stated, amongst other things, the following:
“Today, that is to say 21 January [2012], at about lunch time, Sirazhudin Aliyev, who was born in 1988, and Gazimagomed Abdullayev, who was born in 1988, left home in a Lada Kalina automobile with the registration numbers E261KP 05 RUS and drove in the direction of the Eastern Market [in Makahchkala] ...
However, when they were in their car in the vicinity of the Eastern Market, seven or eight unidentified persons carrying firearms and wearing masks and camouflage uniforms forced them out of their car and took them away in two [one white, one black] Lada Priora cars.
The Lada Kalina car of Gazimagomed Abdullayev was also taken away by those persons ...
In the light of the above, we are seriously concerned that our children could have been unlawfully deprived of their liberty by officials of law-enforcement agencies, [or] special services and subjected to torture or ill-treatment.
On the basis of the above, we request that this complaint be examined ... and that a criminal case be opened ... [and that] the perpetrators be identified and prosecuted ...” 13.  On 21 January 2012 an operational search officer from the Leninskiy district police station reported to the head of the station that the duty officers had received a telephone call concerning an abduction. Upon arrival at the crime scene he had spoken on the telephone to the woman who had called about the incident. The woman had told him that she had called the police by mistake and asked to be left alone. The operational search officer further stated that after talking to local residents, he had been unable to find any witnesses to the abduction. 14.  On 21 January 2012 the investigators questioned the first applicant’s wife, Ms T.A., who stated that she had a son, Sirazhudin Aliyev, and a daughter, Ms Zaira Aliyeva. In 2011 her daughter had been arrested by the Dagestan Federal Security Service (Управление Федеральной Службы Безопасности по Республике Дагестан (ФСБ)) (hereinafter “the FSS”) on suspicion of involvement with illegal armed groups but released ten days later without being charged. At about 5 p.m. on 21 January 2012 a young man had arrived at the store where T.A. had been working and asked her to dial Mr Sirazhudin Aliyev’s mobile number. She had tried, but he had not got through to him. Then the man had told her that her son had been abducted by men in special uniforms and masks. After that the young man had left. According to T.A., her son had not had any enemies or unpaid debts. 15.  On 21 January 2012 the investigators questioned the mother of Gazimagomed Abdullayev, Ms P.A., who stated that she had not witnessed the abduction and had learned of it from her relatives. 16.  On 21 January 2012 the investigators questioned Gazimagomed Abdullayev’s brother, Mr G.A., who stated that he had not witnessed the abduction but had learned of it from his relatives. 17.  On 22 January 2012 the investigators examined the crime scene. No evidence was collected. 18.  On 22 January 2012 the investigators questioned six local residents who owned black Lada Priora VAZ cars about their possible involvement in the abduction. No information indicating such involvement was obtained. 19.  Between 22 and 24 January 2012 the investigators questioned several salespersons and taxi drivers who had been working in the vicinity of the crime scene on the date of the abduction. All of them stated that they had not witnessed the incident. 20.  On 25 January 2012 a local religious association complained to the President of Dagestan on behalf of the applicants. In its letter it stated that Sirazhudin Aliyev and Gazimagomed Abdullayev had been abducted at the Eastern Market on 21 January 2012 and that the abductors, who had fired one gunshot, had been, “judging by all indications, from law‑enforcement agencies”. In the end of January 2012 this complaint was forwarded to the investigators for examination and included in the investigation file. 21.  On 29 January 2012 the investigators questioned the first applicant, who provided them with a detailed account of the abduction, as related to him by a female witness named Fatima (in the documents submitted also referred to as “Fatimakhanum”), according to whom his son, Sirazhudin Aliyev, and his son’s friend, Gazimagomed Abdullayev, had been abducted by officers from the traffic police. The abductors had been in black masks and had fired one gunshot. The two young men had been forced by them into two separate (one black, one white) Lada Priora VAZ cars with registration numbers indicating that they were from the Stavropol region. According to the Government’s submission of 12 September 2012, on an unspecified date between January and August 2012 the investigators had tried to question the witness, but to no avail, as she had left her place of permanent residence and moved elsewhere. 22.  On 31 January 2012 the Investigations Department initiated a criminal investigation into the abduction under Articles 126 and 162 of the Criminal Code (kidnapping and highway robbery) and the case file was given the number 20150. 23.  On 2 February 2012 the investigators questioned Ms M.A., who stated that on 21 January 2012 she had been a passenger on local minivan bus no. 4 (together with other passengers); after the minibus had pulled up next to the market she had seen two young men on the ground being handcuffed. She had immediately called the police and reported the incident, adding that a tall man of athletic build in a black face mask had been standing next to the two young men, but that she had not managed to clearly note the features of the other men who had participated in the incident. 24.  On 4 February 2012 the investigators questioned the second applicant, who stated that she had learned from her relatives of her husband’s abduction. On 28 January 2012 she had arrived at the house of the parents of her abducted husband; after her arrival, men in face masks had told her to go with them to the Kirovskiy district police station in Makhachkala. She had agreed to go with them, accompanied by her brother, Mr G.G.; however, instead of the police station, they had been taken to the CTC, where she had been questioned about telephone numbers that had been called by her abducted husband. After that she had been photographed, samples of her hair and nails had been taken and then she and her brother had been released. 25.  On 9 and 10 February 2012 the applicants lodged complaints in respect of their relatives’ abduction with the Dagestan Minister of the Interior (Министерство Внутренних Дел Республики Дагестан) and the FSS. They described the circumstances of the abduction and asked to be told whether the police and FSS officers had participated in it. 26.  On 15 February 2012 the first applicant was granted victim status in the criminal case and questioned. He provided a detailed account of the abduction that was similar to that submitted to the Court. In particular, he stated that he had not been present during the incident but had learned of it from his wife. According to her, the abductors had been in the uniforms of the traffic police in VAZ cars (the Lada Priora model – one white and one black) with registration numbers containing the digits 177 or 777, indicating that they were from the Stavropol region. The group of seven or eight abductors had stopped a car containing Sirazhudin Aliyev and Gazimagomed Abdullayev, forced them out, put them into their own vehicles and driven off. A few minutes later someone had driven the abducted men’s car away. From an unidentified source the first applicant learned that certain lawyers were assisting in the release of the abducted men. He had been told by those lawyers to meet with someone at 7 p.m. on 3 February 2012 in a VAZ car (the Lada Priora model) in order to receive information about his son. When the first applicant had gone to the meeting, he had spoken with an unidentified man who had told him that for two days after the abduction Sirazhudin Aliyev and Gazimagomed Abdullayev had been detained at the CTC and that then they had been transferred to the North Caucasus Headquarters of the CTC in the Stavropol region under the command of General Chenchik. According to the applicant, neither he nor his wife had found that information credible; the abductors had most probably not been traffic police officers but could have belonged to other law-enforcement agencies and had simply dressed in traffic police uniforms. 27.  On 17 February 2012 the second applicant was granted victim status in the criminal case. She stated that she had learned of the abduction from her relatives. On 28 January 2012 she had gone to the parents of her husband and discovered that at least six law-enforcement officers had been conducting a search of their house and that the head of the group had been a certain Mr A.G. The latter had then told the second applicant that she had to go with them to the police station to provide a statement concerning someone who had allegedly been hiding in her flat, as he was wanted by the authorities for the murder of an FSS officer. The second applicant, her child and her brother, Mr G.G., had been taken to the CTC headquarters, where she had been questioned about telephone numbers that had been dialed by her husband. She had then been fingerprinted and samples of her nails and hair had been taken; then she had gone home. 28.  On 26 February 2012 the investigators questioned the second applicant’s mother, Ms B.M., who stated that she had not witnessed the abduction and had learned of it from her relatives. She further stated that on 28 or 29 January 2012 her house had been searched by representatives of a law-enforcement agency looking for a man suspected of killing the above‑mentioned FSS officer. 29.  On 8 and 17 April 2012 the investigators questioned salespersons Ms Z.G., Ms S.B., Ms I.S., Ms A.G. and Ms Z.R., all of whom stated that they had not witnessed the abduction. 30.  Between 29 April and 15 May 2012 the investigators questioned three other salespersons and three taxi drivers, all of whom stated that they had not witnessed the abduction. 31.  On 18 May 2012 the investigators questioned operational search officer Mr A.G. of the CTC, who stated that the Abdullayev family had been known to them as adherents of illegal armed groups. At the end of January 2012 he had participated in a search of their house conducted together with police officers from the Kirovskiy district police station in Makhachkala (see paragraph 27 above). The search had been conducted in connection with an investigation into the murder of an FSS officer. After the search, the second applicant and her mother had been taken to the CTC headquarters to provide statements to the investigators. The witness had learned of the abduction of Gazimagomed Abdullayev during the conduct of the search. 32.  On 31 May 2012 the criminal investigation was suspended; on 31 August 2012 it was resumed following criticism voiced by the supervisory authorities. Explaining the decision to overrule the suspension of the investigation the deputy head of the Dagestan Investigations Department stated, inter alia, the following:
“... the decision to suspend the investigation was taken in violation of Article 208 § 5 of the Criminal Procedure Code – that is to say prematurely, – given that all possible steps had not been taken ...
In connection with the above, the decision should be overruled as unlawful and the investigation should be resumed.
It is necessary that the investigators take the following steps:
-  take additional measures to establish the whereabouts and question [the applicants] and the persons with whom on 3 February 2012 [the first applicant] had a meeting concerning the abduction of Sirazhudin Aliyev and Gazimagomed Abdullayev;
-  question Sirazhudin Aliyev’s friends, Mr T., Mr S. and Mr D.;
-  [(after obtaining court authorisation),] examine the list of mobile telephone calls made by Sirazhudin Aliyev and Gazimagomed Abdullayev ...” 33.  On 30 September 2012 the investigation was suspended again. None of the witnesses specified in the above decision to resume the proceedings were questioned. The applicants were informed of the suspension. 34.  On 1 October 2012 the investigation was resumed again after criticism from the deputy head of the Dagestan Investigations Department, who stated, inter alia, the following:
“... in violation of part 5 of Article 208 of the Criminal Procedure Code the investigation failed to take all the investigative steps possible to establish the [identity of the perpetrators]; therefore, the decision to suspend the proceedings should be overruled as unlawful.
It is necessary that the investigation take the following steps: 1. Question Sirazhudin Aliyev and Gazimagomed Abdullayev’s close relatives to find out whether ... they received any [conditions to be met in respect of] their return;
... 4. Ask the Russian Federal Service for the Execution of Sentences whether the abducted men are being detained in their facilities;
... 35.  On 5 November 2012 the investigation was again suspended without any of the supervisory authorities’ orders given on 1 October 2012 being carried out, except for the forwarding of requests for information to various State authorities. The applicants were informed of the suspension. 36.  On 28 January 2013 the investigation was again resumed following criticism from the supervisory authorities (this time the Leninskiy district prosecutor in Makhachkala), who pointed out the following:
“... the investigation of the criminal case has been suspended on three occasions for failure to establish the identity of the perpetrators. On each occasion, the decision was similar to the previous ones, without the [requested] steps having been taken.
Such circumstances demonstrate that the investigators violated Article 61 of the Criminal Procedure Code concerning the time-limit for investigation and demonstrate a lack of oversight on the part of the supervisors from the Investigation Committee.
The last decision to suspend ... taken on 5 November 2012 ... should be overruled as unlawful for the following reasons.
An examination of the case file showed that the investigation of the criminal case had been conducted with violations of the criminal procedure regulations. For instance, prior to the suspension of the proceedings, the investigator should have taken all the steps possible in the absence of the suspect or accused and taken all the steps necessary to establish the identity of the perpetrator.
However, the investigation [in the present case] failed to question close relatives of Sirazhudin Aliyev and Gazimagomed Abdullayev ...
The list of mobile telephone calls [made by the abducted men] has not been examined;
Replies to ten requests for information forwarded to the law-enforcement agencies and State bodies have not been received ...” 37.  On 4 February 2013 the investigators were ordered to comply with the above instructions within one month and the investigation of the criminal case was forwarded to the investigations department of the Leninskiy district prosecutor’s office in Makhachkala. 38.  On 7 February 2013 the investigators examined a list of mobile telephone calls made by the abducted men. 39.  On 14 February 2013 the second applicant asked the investigators to provide her with copies of documents from the investigation file concerning the disappearance of her husband stating that she needed them in order to initiate civil proceedings to recognise him a missing person and to obtain compensation for the loss of her family’s breadwinner. On 15 February 2013 her request was granted. 40.  On 18 February 2013 the investigators again questioned the second applicant’s mother and Gazimagomed Abdullayev’s mother-in-law, Ms B.M., who confirmed her earlier statement (see paragraph 28 above) and stated that she and her relatives had not heard from Gazimagomed Abdullayev since his abduction. 41.  On 4 March 2013 the investigation was suspended again. The applicants were informed thereof. 42.  On 12 August 2013 the investigation was again resumed after criticism voiced by the supervisory authorities. The decision overruling the suspension again enumerated the steps not taken by the investigators, in violation of the previously given orders, and stressed that the proceedings were to be resumed, having been adjourned unlawfully. The investigators were instructed to take eighteen steps listed in a special order issued on the same date. 43.  On 3 September 2013 the investigators again questioned Gazimagomed Abdullayev’s brother, Mr G.A. (see paragraph 16 above), who stated that at about 4.30 p.m. on 21 February 2012 he had learned of the abduction from his uncle Mr R.A. The two of them, together with the mother of Sirazhudin Aliyev, had gone to see a lawyer named Shamil. According to G.A., Mr R.A. had had information about the names of the eyewitnesses to the abduction. 44.  On 3 September 2013 the investigators questioned Gazimagomed Abdullayev’s uncle, Mr R.A., who stated that on 21 January 2012 he had been in his store when two young men had told him that Gazimagomed Abdullayev and Sirazhudin Aliyev had been forced into VAZ cars (one the Lada Priora model and one the 2110 model) and taken away. Gazimagomed Abdullayev’s mobile telephone had been switched off. His car had been taken away by the abductors. After that Mr G.A. and the mothers of the abducted men had gone to a lawyer named Shamil, who had contacts with human rights organisations. 45.  On 27 August 2013 the investigators requested court authorisation to obtain a list of mobile telephone calls made by the first applicant between 20 January and 20 February 2012. 46.  On 13 September 2013 the investigators obtained and examined the list of the first applicant’s mobile telephone calls. 47.  On 14 September 2013 the investigators again questioned the first applicant, who confirmed his earlier statements (see paragraph 21 and 26 above). In addition, he provided a detailed description of his son’s appearance. 48.  On 17 September 2013 the investigators again questioned Ms M.A., who confirmed her earlier statement (see paragraph 23 above) and added that the abduction had been witnessed not only by her, but also by the other passengers of minivan bus no. 4; however, she had been the only one who had called the police about the incident. 49.  On 18 September 2013 the investigators questioned Ms T.A. (the first applicant’s wife and the mother of Sirazhudin Aliyev), who stated that her daughter, the sister of Sirazhudin Aliyev, had been detained by the FSS on suspicion of involvement in illegal armed groups and an extremist religious movement. In the evening on that date, she had learned of her son’s abduction. From the very beginning, she had suspected that officers of law‑enforcement agencies had perpetrated it. 50.  On 19 September 2013 the investigators again suspended the proceedings for failure to establish the identity of the perpetrators. The applicants were informed of the suspension. 51.  On 28 October 2013 the investigation was resumed again. The relevant decision stated that the proceedings were to be resumed because of “the need to verify the involvement of traffic police officers in the abduction, given that witnesses to the incident stated that the perpetrators looked like policemen”. The applicants were informed of that decision. 52.  On 8, 18 and 24 November 2013 the investigators questioned traffic police officers G.O., Z.G. and K.K., all of whom stated that in January 2012 they and their colleagues had not conducted any special operations and that they had not heard of the abducted men before. 53.  On 28 November 2013 the investigators again suspended the proceedings and informed the applicants of the suspension. 54.  On 20 December 2013 the investigation was again resumed after criticism voiced by the supervisory authorities. The decision stated, amongst other things, the following:
“... the decision to suspend the investigation is premature and unsubstantiated for the following reasons:
The investigators failed to carry out in full the [supervisory authorities’] orders of 12 August 2013 ...
[They] failed to question Ms Z.A., who organised the [first applicant’s] meeting with the persons who had pointed out that the abduction had been perpetrated by officers of law-enforcement agencies ...
The witness statement of Ms M.A. was not re-enacted at the crime scene in order to establish the circumstances of the incident in detail ...
Other numerous deficiencies in the investigation have not been remedied ...” 55.  On 1 February 2014 the investigators again questioned the first applicant, who confirmed his earlier statements (see paragraphs 21, 26 and 47 above). He also stated that the perpetrators of the abduction of Sirazhudin Aliyev had most probably been officers of law-enforcement agencies and that his daughter, Ms Zaira Aliyeva, had been killed by law‑enforcement agents on 18 January 2014 during a special operation in Makhachkala. 56.  On 2 February 2014 the investigators again questioned Gazimagomed Abdullayev’s brother, Mr G.A., who confirmed his earlier statements (see paragraphs 16 and 43 above). 57.  On 4 and 8 February 2014 the investigators again questioned Ms B.M. and Ms M.A., both of whom confirmed their earlier statements (see paragraphs 28 and 48 above). 58.  On 8 February 2014 the investigators again examined the crime scene (see paragraph 17 above). No evidence was collected. 59.  On various dates in February 2014 the investigators obtained samples of blood and saliva from the abducted men’s relatives for expert genetic evaluation and inclusion in the regional DNA database. 60.  On 8 February 2014 the investigators examined the first applicant’s house. No evidence was collected. 61.  On 9 February 2014 the investigation was again suspended. 62.  On 15 February 2014 the investigation was resumed following criticism by the supervisory authorities. The relevant decision stated that the suspension was premature and unlawful and that the investigators had failed to take a number of necessary steps; moreover, they had “failed to correct numerous shortcomings in the investigation.” 63.  On various dates in March 2014 the investigators questioned the abducted men’s neighbours, Mr O.G., Mr M.M., Mr S.G. and Mr B. Kh., whose statements did not yield any new information. 64.  On 15 April 2014 the investigation was suspended again. 65.  On 23 April 2014 the investigation was again resumed following criticism by the supervisory authorities. The reasoning for the decision to order the resumption of the investigation decision stated that the suspension had been premature and unlawful and that the investigators had failed to re‑qualify the crime from that of abduction under Article 126 of the Criminal Code to that of murder under Article 105 of the Criminal Code. (The investigators should have done this, given that the abducted men had been missing for more than two years.) 66.  On 28 April 2014 the investigators questioned the abducted men’s acquaintance, Mr Z. Sh., whose statement did not yield any new information. 67.  On 11 May 2014 the investigators complied with the supervisory authorities’ orders of 23 April 2014 and re-qualified the crime committed in respect of Sirazhudin Aliyev and Gazimagomed Abdullayev from that of abduction to that of murder. 68.  On 12 May 2014 the investigators again questioned the second applicant, who confirmed her earlier statements (see paragraphs 24 and 27 above). 69.  On 17 February 2014 the samples of blood and saliva obtained from Sirazhudin Aliyev and Gazimagomed Abdullayev’s relatives were examined (see paragraph 59 above). 70.  On 24 May 2014 the investigation of the criminal case was suspended again. The applicants were informed of the suspension. 71.  On 25 June 2014 the Leninskiy district prosecutor in Makhachkala examined the criminal case file and concluded that the suspension of the proceedings had been lawful. 72.  As can be seen from the documents submitted the proceedings are still pending. 73.   According to the applicants, the investigators failed to inform them of the course of the criminal proceedings in a timely manner.