<text>  A millionaire hospital executive stabbed to death his wife then set fire to their New Jersey home in a murder-suicide, officials have ruled - despite the couples children insisting they were both murdered. John Sheridan, 72, the CEO of Cooper Health System, and his 69-year-old wife, Joyce Sheridan, were found dead, with seven stab wounds between them, in their blazing Skillman house last September. Mrs Sheridan, a retired high school teacher, died from a stab wound to her chest, while her husband, an ally of state governor Chris Christie, passed away from sharp force injuries and smoke inhalation. On Friday, prosecutors ruled Mr Sheridan had attacked his wife with a knife in the seconds leading up to their deaths, which occurred just a day after the couple had decorated their home for Halloween. Murder-suicide: John Sheridan left, 72 ,stabbed to death his wife, Joyce right, 69, then set fire to their home in a murder-suicide, officials have ruled - despite the couples children insisting they were murdered . Crime scene: Mr Sheridan, the millionaire CEO of Cooper Health System, and his wife were found dead, with seven stab wounds between them, in their blazing Skillman, New Jersey, house pictured last September . Mrs Sheridan suffered eight wounds to her head, a stab injury to her chest that perforated her aorta, wounds to her hands that were characterized as defensive in nature and bruising, officials said. She was ruled to have died before the fire started on September 28. After killing his wife of 47 years with a carving-type knife, Mr Sheridan then doused the room with gasoline and set it alight, it is said. Mr Sheridan finally stabbed himself with a sharp item three times in the torso and neck area, causing a small perforation to the right jugular vein, prosecutors ruled. He was then overcome by thick smoke. Despite the murder-suicide ruling, announced by Somerset County Prosecutor Geoffrey Soriano on Friday, the four grown sons of the Sheridans have released a statement challenging the findings. The men, including Mark Sheridan, who is a prominent Republican election law lawyer, said they were not satisfied with the result of the investigation and still dont know who killed their parents. The conclusion announced today fails to provide those answers, the sons statement said. Connections: Mr Sheridan left is pictured with, from left, George Norcross III, New Jersey Governor Chris Christie and Dr. Paul Katz during an event in 2012. He was an influential member of the Republican party . Revelation: On Friday, prosecutors said in a statement pictured that Mr Sheridan had fatally stabbed his wife on the day of their deaths, which occurred just a day after they had decorated their home for Halloween . It is nothing more than an expedient way for the Prosecutors Office to close its file and put an end to its embarrassing bungling of this murder investigation in the hope that our family, the citizens of Somerset County and the press will stop inquiring about what actually happened. Authorities discovered the Sheridans bodies in their master bedroom after responding to a report of a fire shortly before 6.15am. Mr Sheridan was found lying face-up at the foot of the couples bed. The top portion of a two piece, armoire dresser was discovered resting on his body, according to officials. Seconds later, Mrs Sheridan was found lying face-up on the floor to the left of the bed. The wealthy couple did not leave behind a will, while two knives were found in the master bedroom near their bodies. Following the grim discoveries, Sorianos office spent six months investigating. Damaged: After killing his wife with a carving-type knife, Mr Sheridan set fire to their home with gasoline and matches, it is said. Above, a police vehicle is seen stationed outside the burned property on September 29 . Police at the scene: Mr Sheridan finally stabbed himself with a sharp item three times in the torso and neck area, causing a small perforation to the right jugular vein, officials ruled. He was then overcome by smoke . On Friday, the office said some of the 180 interviews carried out during the investigation had revealed Mr Sheridan had been withdrawn and acting unusually in the days before the deaths. He was described as being out of character, very upset and with an attitude of resignation. The investigation also found no signs of a break-in at the Montgomery County home, officials said. However, the couples sons have argued some key evidence is missing in the case. The Sheridans owned two homes - the 512,000 property where the fire unfolded and another in New York. Mr Sheridan was president and CEO of Camden-based Cooper University Health Care, which has more than 700 physicians and serves more than half a million patients a year, when he died. Memorial service: The couples joint memorial service drew hundreds of mourners including Gov Christie and four of his predecessors, ex-governors Jim Florio, Christine Whitman, Tom Kean and Don DiFrancesco . Last year, NJBiz valued his company at 913million. Mr Sheridan, a Republican, was also an important political figure who served as general counsel to the New Jersey Turnpike Authority. The couples joint memorial service drew hundreds of mourners including Gov Christie and four of his predecessors, ex-governors Jim Florio, Christine Whitman, Tom Kean and Don DiFrancesco. As well as their four sons, the Sheridans left behind three grandchildren. In a case unrelated to the fire, one of the sons, Matthew Sheridan, 40, was arrested hours after their deaths for cocaine possession and possession of drug paraphernalia found in his car. Prosecutors have not yet pursued the charges against Mr Sheridan, but have five years to do so. 