Federal prosecutors announced Friday they will seek the death penalty for a former University of Illinois graduate student accused of kidnapping, torturing and killing a visiting scholar from China in June. 
 
 In making the announcement, prosecutors alleged for the first time that Brendt Christensen “choked and sexually assaulted” another victim in 2013 in central Illinois. He also has claimed “additional victims” and expressed a “desire to be known as a killer,” according to prosecutors. 
 
 Christensen, 28, who is being held without bond, had tentatively been set to go to trial Feb. 27 in federal court in Urbana on a charge of kidnapping resulting in a death stemming from the disappearance of 26-year-old Yingying Zhang, whose body has not been found. 
 
 The decision to seek the death penalty — which required the approval of U.S. Attorney General Jeff Sessions — means that the trial will likely be delayed for months. 
 
 The death penalty was abolished in Illinois state court in 2011 after years of allegations of deep flaws in the state’s justice system. In certain cases, though, it remains a tool for federal prosecutors, but its use in federal courts is still rare. It also can take years for an execution to actually be carried out. 
 
 The last person to be sentenced to death in a federal courtroom in Illinois was Dr. Ronald Mikos, who was convicted in 2005 in Chicago of murdering a former patient to keep her from testifying against him in a Medicare fraud trial. 
 
 Mikos, 69, whose appeal to the U.S. Supreme Court was denied nearly a decade ago, is still awaiting execution in federal prison in Terre Haute, Ind., federal records show. 
 
 The announcement in Christensen’s case marks at least the third time in recent weeks that Sessions has opted to push for the death penalty. Earlier this month, it was revealed prosecutors would seek the death penalty against Billy Arnold, an alleged gang member accused of killing two rivals in Michigan. In December, Sessions greenlighted pursuit of the death penalty against Jarvis Wayne Madison, a Florida man who allegedly kidnapped and killed his estranged wife. 
 
 In their five-page motion Friday, prosecutors said the death penalty was warranted because Christensen “is likely to commit criminal acts of violence in the future that would constitute a continuing and serious threat to the lives and safety of others.” 
 
 No details of the alleged 2013 sexual assault by Christensen were provided other than the initials of the victim, “M.D.” The alleged assault occurred the year Christensen was admitted to the university’s highly competitive physics graduate program. 
 
 Four years later, Zhang's sudden disappearance rattled the U. of I. campus and sent shock waves throughout China. 
 
 Zhang, who began her research appointment last April, tried unsuccessfully to flag down a bus before walking to another stop the afternoon of June 9. Shortly after, federal authorities allege, Christensen approached Zhang in his black Saturn Astra sedan and lured her inside. 
 
 Surveillance video from a nearby parking garage captured the exchange in which Zhang could be seen speaking to the driver for several moments before getting into the front passenger seat. 
 
 The investigation focused on Christensen after police concluded his Saturn was the car seen in the video. He initially told the FBI he was home all day playing video games on the day Zhang disappeared. 
 
 Yingying Zhang, 26, a visiting scholar at the University of Illinois, has been missing since June 9, 2017. Authorities say she is presumed dead. Brendt Christensen, 28, has been charged with kidnapping Zhang. 
 
 When he was questioned a second time, Christensen changed his story, telling agents he got the date mixed up, according to court records. He said he was driving on campus, came across an Asian woman looking distressed and offered her a ride because she said she was late to an appointment, authorities said. Christensen said the woman panicked after he made a wrong turn, and he let her out of his car a few blocks from where they met, prosecutors said. 
 
 Meanwhile, police searched Christensen’s car and determined that the area where Zhang would have been sitting had been cleaned in a way to conceal evidence, according to prosecutors. Police also searched his phone and found visits to a sadomasochism fetish website with discussion threads on kidnapping fantasies, prosecutors said. 
 
 On June 29, Christensen attended a campus rally for Zhang with a girlfriend, who unbeknownst to him was wearing an FBI wire. He was captured on audio recordings describing his "ideal victim" as he pointed out people in the crowd, prosecutors have previously said. 
 
 Other recordings made that day captured Christensen admitting to having kidnapped Zhang and describing how she fought back as he held her against her will, according to prosecutors. 
 
 Earlier this week, a defense filing revealed that a few hours before Zhang’s kidnapping, a female U. of I. graduate student reported to police that a man wearing aviator sunglasses had pulled up to her in a black sedan and flashed a badge. She refused to get in the car and he drove off. 
 
 A few days later, the woman picked out Christensen’s photo from among six shown her by the FBI, but Christensen’s lawyers are seeking to block the testimony, saying she couldn’t be certain because of the sunglasses. 
 
 She did say that of the six photos, Christensen "shared the most characteristics" of the man because of his "short, dark hair and tan face," the filing said. 
 
 jmeisner@chicagotribune.com 
 
 Twitter @jmetr22b 
 
 RELATED: Earlier abduction attempt reported on day Chinese scholar went missing at U. of I. » 
 
 Parents of missing Chinese scholar: 'I don't know how to spend the rest of my life without my daughter' » 
 
 At vigil for missing Chinese scholar, suspect talked about 'ideal victim,' prosecutor says » ||||| Former University of Illinois graduate student Brendt Christensen could be eligible for the death penalty if convicted on new charges filed Tuesday alleging he kidnapped and killed a visiting scholar from China in June. 
 
 Christensen, 28, of Champaign, was charged in a superseding indictment with one count of kidnapping resulting in a death stemming from the disappearance of 26-year-old Yingying Zhang, whose body has not been found. 
 
 The federal grand jury returned the four-page indictment with the special finding that Christensen committed the offense “in an especially heinous, cruel or depraved manner, in that it involved torture or serious physical abuse to the victim,” and that the crime occurred after “substantial planning and premeditation.” 
 
 The indictment also charged Christensen with two new counts of making false statements to FBI agents. 
 
 Christensen could face the death penalty if convicted on the new kidnapping charge, although the decision whether to seek it will be made at a later date by U.S. Attorney General Jeff Sessions, according to a news release from the U.S. attorney’s office in Urbana. If the death penalty is not sought, a conviction on the kidnapping count would call for mandatory life without parole. 
 
 Christensen, who is being held without bond, is tentatively set to go to trial Feb. 27 before U.S. District Court Judge Colin Bruce. Reached by telephone Tuesday, his lawyer, Robert Tucker, said he had not seen the superseding indictment and had no comment. 
 
 The new charges were the latest twist to a case that rattled the University of Illinois campus and sent shock waves throughout China. 
 
 Prosecutors allege Zhang, who began her research appointment in April was on her way to sign a lease at an apartment building the afternoon of June 9 and unsuccessfully tried to flag down a bus before walking to another stop. Shortly after, federal authorities allege that Christensen approached Zhang in his car and lured her inside. 
 
 Surveillance video from a nearby parking garage captured the exchange in which Zhang could be seen speaking to the driver for several moments before getting into the front passenger seat. One of Zhang's professors reported her missing by that evening, after several calls and texts went unanswered. 
 
 The investigation homed in on Christensen after police concluded his Saturn Astra was the car seen in the footage. He initially told the FBI he was home all day playing video games on the day Zhang disappeared. When he was questioned a second time three days later, Christensen changed his story, telling agents he was driving on campus, came across an Asian woman looking distressed and offered her a ride because she said she was late to an appointment. 
 
 Christensen said the woman panicked after he made a wrong turn, and he let her out of his car a few blocks from where they met. Meanwhile, police also searched his car and determined that the area where Zhang would have been sitting had been cleaned in a way to conceal evidence, FBI agents alleged in court documents. 
 
 Police also searched his phone and found visits to a sadomasochism fetish website with discussion threads on kidnapping fantasies. 
 
 The FBI also conducted audio surveillance on Christensen for several days, including when he attended a campus walk and vigil in Zhang's honor on June 29. There, Christensen was caught on tape pointing out people in the crowd and describing his "ideal victim." 
 
 Other surveillance tapes recorded Christensen allegedly admitting to having kidnapped Zhang, and describing how she fought back as he held her against her will, prosecutors said. 
 
 Police and prosecutors have not revealed the source of the recordings. 
 
 jmeisner@chicagotribune.com 
 
 Twitter @jmetr22b ||||| Professor Lance Cooper, associate head of graduate programs in the department of physics at the University of Illinois at Urbana-Champaign, discusses former student Brendt Christensen on July 1, 2017. Christensen has been charged with allegedly kidnapping Yingying Zhang, a visiting scholar at the university who disappeared three weeks ago and now is presumed dead. (Abel Uribe / Chicago Tribune) 
 
 Professor Lance Cooper, associate head of graduate programs in the department of physics at the University of Illinois at Urbana-Champaign, discusses former student Brendt Christensen on July 1, 2017. Christensen has been charged with allegedly kidnapping Yingying Zhang, a visiting scholar at the university who disappeared three weeks ago and now is presumed dead. (Abel Uribe / Chicago Tribune) 
 
 Federal authorities have arrested and charged a 28-year-old man with kidnapping Yingying Zhang, a visiting scholar at the University of Illinois who disappeared three weeks ago and now is presumed dead. Brendt Christensen, a former Ph.D. candidate who had studied physics at the university, was arrested late Friday, according to a news release from the Department of Justice. A federal complaint also was filed Friday in the Central District of Illinois accusing him of kidnapping Zhang from the Urbana-Champaign campus the afternoon of June 9. Christensen's former academic advisor, professor Lance Cooper, associate head for graduate programs in the Department of Physics, was part of the committee that admitted Christensen to the program in fall 2013. "Nobody saw this coming," Cooper said Saturday. Zhang, 26, arrived at the University of Illinois in late April to contribute to research in the Department of Natural Resources and Environmental Sciences. Her appointment as a scholar was through April 2018. She originally was from Nanping, a small city in the Fujian province in southeast China; a university spokeswoman, Robin Kaler, said Zhang was considering entering a doctoral program at U. of I. Tina Chu, acting executive director of the Chinese-American Museum of Chicago, said Zhang’s father, boyfriend and aunt came from China to Illinois during the search. Chu met the family and helped translate for them at a vigil held in Chinatown on June 24, and described them as “good, hardworking people.” They had a very positive attitude that they would find Yingying, Chu said. Chu has not seen the family since then, but said the news must be devastating. Students at the University of Illinois at Urbana-Champaign react July 1, 2017, to the alleged kidnapping of visiting scholar Yingying Zhang. (Abel Uribe/Chicago Tribune) Students at the University of Illinois at Urbana-Champaign react July 1, 2017, to the alleged kidnapping of visiting scholar Yingying Zhang. (Abel Uribe/Chicago Tribune) SEE MORE VIDEOS “This is their hope,” she said. “I don’t know how they’re going to take it.” “It is scary, shocking news for the Chinese in China,” she said. “People are talking, saying, ‘You’ve got to be careful, watch out for your safety.’ It makes us feel really insecure.” Some 5,600 Chinese are enrolled at U. of I., more than at any other U.S. college, according to government data. "This is a senseless and devastating loss of a promising young woman and a member of our community," U. of I. Chancellor Robert Jones said in a statement. "There is nothing we can do to ease the sadness or grief for her family and friends, but we can and we will come together to support them in any way we can in these difficult days ahead." The day she disappeared, Zhang was at Turner Hall, where she conducted her research, between 8:30 a.m. and around 12:30 p.m., according to the affidavit. She then went back to her apartment for lunch, authorities say. Zhang left shortly after, heading to a different apartment complex in Urbana to sign a lease. She texted the building manager around 1:39 p.m. to say she was running late, according to the affidavit, and planned to arrive around 2:10 p.m. University of Illinois police say they believe Yingying Zhang, 26, has been killed. A 28-year-old Champaign man has been charged with the Chinese scholar's kidnapping at the University of Illinois. University of Illinois police say they believe Yingying Zhang, 26, has been killed. A 28-year-old Champaign man has been charged with the Chinese scholar's kidnapping at the University of Illinois. SEE MORE VIDEOS Video showed Zhang boarding a Champaign-Urbana Mass Transit District bus around 1:35 p.m. She took the Teal line bus from Orchard Downs and exited at West Springfield and North Mathews avenues at 1:52 p.m., police said. Four minutes later, Zhang was seen on video trying to flag down another MTD bus, but it passed her without stopping. The affidavit states the bus was a Limited Line bus and probably did not stop because Zhang was standing on the wrong side of the street to board. Unable to catch the bus, Zhang walked north to the intersection of North Goodwin Avenue and West Clark Street, where she stood at another designated MTD bus stop on the southeast corner. According to the MTD website, the Goodwin and Clark stop is designated for the Illini Limited weekday daytime route, which runs only during university breaks and summer sessions. Around 2 p.m., a black Saturn Astra, which authorities say was driven by Christensen, was seen on surveillance video from a nearby building driving east on West University Avenue, then turning onto Goodwin and then to Clark Street, past where Zhang was standing. The Astra then reappeared on surveillance video driving west on West Main Street, then turning back onto Goodwin. Authorities previously said the car appeared to be circling the area before approaching Zhang. Minutes later, the car pulled off to the side of the road where Zhang was standing. Video from a parking garage across the street showed Zhang speaking with the driver for about a minute before she got into the front passenger seat, authorities say. The car then continued driving north on Goodwin Avenue. Zhang was not seen or heard from after that, police said. The apartment manager texted her at 2:38 p.m. and got no response, according to the affidavit. This undated photo provided by the University of Illinois Police Department shows Yingying Zhang, a scholar visiting from China, who has been missing since June 9, 2017, and is now presumed dead. A recent U. of I. graduate has been charged with her kidnapping. This undated photo provided by the University of Illinois Police Department shows Yingying Zhang, a scholar visiting from China, who has been missing since June 9, 2017, and is now presumed dead. A recent U. of I. graduate has been charged with her kidnapping. An associate professor reported Zhang missing to U. of I. police at 9:24 p.m. A responding officer spoke to the professor and several of Zhang’s friends, all of whom said they knew she was heading to sign the apartment lease but had not been able to contact her for several hours. The officer went to Zhang’s current apartment, which was locked and vacant, the affidavit states. Police determined that there were 18 four-door Saturn Astras registered in Champaign County, one of which was in Christensen’s name. Police went to Christensen's home the night of June 12 and asked him where he was when Zhang was last seen June 9. Christensen initially said he could not remember, then told police he was either sleeping or playing video games all day. Police searched the car but did not locate or take anything from it, the affidavit states. On June 14, police noted in the surveillance footage that the Astra had a sunroof and a cracked hubcap on the front passenger side. Authorities returned to Christensen’s home in the 2500 block of West Springfield Avenue and saw that his Astra also had a cracked hubcap consistent with what police saw in the footage. Police, who had previously noted that Christensen’s car also had a large sunroof, determined that his was the vehicle seen in the surveillance, the affidavit states. Macon County Sheriff's Office via AP Brendt Christensen, 28, of Champaign, Ill. Brendt Christensen, 28, of Champaign, Ill. (Macon County Sheriff's Office via AP) (Macon County Sheriff's Office via AP) Authorities interviewed Christensen on June 15 while the FBI and U. of I. police searched his car. In the interview, Christensen admitted to driving around the U. of I. campus when he saw an Asian woman standing at the corner, looking distressed, the affidavit states. Christensen said he drove up to her and offered her a ride after she said she was late to an appointment. The woman then tried to show Christensen where she needed to go through the map on her phone. Christensen claimed he made a wrong turn at some point and the woman panicked, then he let her out of his car a few blocks from where he picked her up, the affidavit states. 
 
 Authorities also searched Christensen’s home and seized electronics, including his phone, according to the affidavit. The phone’s search history revealed visits to a bondage and sadomasochism fetish website called FetLife and a forum called "Abduction 101," as well as subthreads titled “Perfect abduction fantasy” and "planning a kidnapping," according to the affidavit. The searches to those websites had occurred several weeks before the alleged abduction, around April 19, authorities wrote in the affidavit. In a search of the car, authorities discovered that the front passenger side where Zhang would have been sitting "appeared to have been cleaned to a more diligent extent than the other vehicle doors," the affidavit states, adding that investigators believed this was done to conceal evidence. Authorities began surveilling Christensen on June 16. On June 29, police heard him say on an audio recording that he kidnapped Zhang, brought her back to his apartment and held her in his apartment against her will, according to the affidavit. "Based on this, and other facts uncovered during the investigation of this matter, law enforcement does not believe (Zhang) is still alive," the affidavit states. Federal authorities listed Christensen as 27, but the federal complaint gives his birthday as June 30, which would make him 28 as of Friday. He is scheduled to appear in federal court in Urbana on Monday morning. Bin Xu, 22, a senior from Zhejiang, China, who is studying statistics, said he wished the school would emphasize safety to international students who may be disoriented from being in a new country and naive to potential dangers. Orientations are in English, which can be hard for international students to understand, and Xu said the school forgets how hard it is for students to simply get around the large campus. Xu recalled a time when he was confused about how to get across campus on a particularly snowy day. He said he walked on the street that night to avoid slipping on the ice on the sidewalk and became exasperated to the point where he would have accepted a ride from a stranger. “You shouldn’t be blaming Yingying Zhang for riding in someone’s car,” Xu said in Mandarin. “The school also can’t run away from this. The school’s responsibility is huge. I feel really sorry for Yingying Zhang’s parents.” Zhang's boyfriend has said that she was cautious and wouldn't normally get into a car with a stranger unless duped or forced. Brendt Christensen affidavit (PDF) Brendt Christensen affidavit (Text) Zhang graduated last year with a master's degree in environmental engineering from one of China's elite schools, Peking University Shenzhen Graduate School. She had been doing research on crop photosynthesis, which included using drones to study fields, the university's communications office has said. Those who knew Zhang described her as bright and outgoing. She played guitar and sang in a band called Cute Horse in China. One of her favorite songs was "The Rose," a hit in 1980 for Bette Midler. Zhang's aunt recently told CNN that her niece had ambitions of becoming a professor in her home country. "To be a faculty member in China, there are certain qualifications you have to meet, and as part of that you have to have broad experience in terms of your research and your study," Liqin Ye recalled her niece saying. "And that's probably what motivated her to want to come to the United States." Christensen, similarly, was following a path in academia until he changed course a little more than a year ago. As Christensen’s advisor, Cooper went over his school record and charted out the courses he was to take. Cooper said he didn’t interact with Christensen on a regular basis after the initial semester until spring 2016, when Christensen had a meeting with him to drop out of the Ph.D. program and pursue a master’s degree instead. “Christensen earned a master's degree from the (physics) program in May of 2017 and his affiliation with the department ended that same month,” said Kaler, the university spokeswoman. Christensen also taught introductory courses and discussion sections for four semesters and one summer course. “He was completely normal, there were no complaints about his teaching,” Cooper said. “He was on the excellent teaching list, so he was well-reviewed by his students.” No disciplinary issues were reported about him, and he never had issues showing up for class or getting assignments in on time, Cooper said. “There was nothing remarkable about him as far as I could see,” Cooper said. On what appears to be his LinkedIn page, Christensen described himself as a Ph.D. candidate at U. of I. since January 2014, researching experimental condensed matter physics. Cooper said Christensen mentioned in spring 2016 that he was married and that he and his wife were going to use the next year to decide what their plans were while he completed his master’s program. Christensen worked briefly in a condensed matter physics group, which studied materials and their exotic properties, but transitioned out of that when he dropped his Ph.D. “He never gave any personal reasons,” Cooper said. “I just got the impression that the Ph.D. program was not what he thought it would be and that this was no longer his goal. He didn’t speak about any personal issues.” Cooper said he was shocked when he heard news about Christensen's arrest and said that members of his graduate-level physics class seemed to share that reaction. They had a meeting scheduled for Sunday to brainstorm ideas for sharing their condolences with Zhang's family. Also according to Christensen's LinkedIn page, he received a bachelor of science degree with honors in physics, as well as a degree in mathematics from the University of Wisconsin at Madison, where he was in the Physics Club. The page also describes him as a graduate teaching assistant in physics at U. of I. from 2013 until the present, overseeing about 20 students. Christensen described himself on the page this way: "I am a Ph.D. candidate in experimental condensed matter physics at the University of Illinois at Urbana-Champaign. Currently, I fabricate nanoscale-level devices and perform electrical measurements on them in order to discover new things about mesoscopic physics. These measurements are done with a variety of devices; most notably probe stations and cryogenic systems. Along the way, I utilize an assortment of programs and skills, such as Python, LabVIEW, electron-beam lithography, atomic force microscopy, and much more." Sarah Manzella, 20, who lives in the same apartment complex as Christensen, which is made up of multiple buildings with a central parking lot, said she could not have imagined living so close to the person eventually arrested in connection with Zhang's disappearance.
– University of Illinois graduate student Yingying Zhang disappeared in June. The Chinese woman's body has not been found, but federal prosecutors believe that Brendt Christensen is responsible for her murder—and they announced Friday that, with Attorney General Jeff Sessions' blessing, they will pursue the death penalty in their case against him. The Chicago Tribune looks at just how rare a thing such a conviction and sentence would be. Illinois did away with the death penalty in 2011, and its use in federal court is far from commonplace. More on the case, the move, and the growing allegations against Christensen: The Tribune reports the last instance of the federal sentence being imposed in Illinois court was in 2005, when Dr. Ronald Mikos was found guilty of murdering a one-time patient who was cooperating in a Medicare fraud trial against him. The Supreme Court declined to hear his appeal in 2009, the AP reported at the time, but he still awaits execution.