The sons of Cooper Health System CEO John P. Sheridan Jr. have repeatedly requested that New Jersey authorities overturn a ruling that their father committed suicide on Sept. 28, 2014 - a mission that has turned into a complex legal fight.

Six weeks ago, the Sheridans submitted expert opinion to strengthen their argument that their father was murdered.

The sons are challenging the findings of the New Jersey Medical Examiner's Office and the Somerset County Prosecutor's Office, which announced on March 27, 2015, that Sheridan, 72, fatally stabbed his wife, Joyce, 69, and set the bedroom of their Montgomery Township home on fire. According to state and county authorities, he then took his own life, stabbing himself five times in the neck and torso.

The state autopsy report said he died of "sharp force injuries and smoke inhalation." In early April, the family wrote to the Attorney General's Office, which oversees the medical examiner, to have the suicide ruling changed.

The couple's four sons - Tim, Dan, Matt, and Mark, a lawyer for Squire Patton Boggs in Newark, N.J. - want their father's manner of death changed to undetermined. They believe both parents were killed by an intruder.

Overturning a medical examiner's decision is costly and rarely done, which is why it is unclear how long the challenge will take. According to the New Jersey Department of Health, in 2014 nearly 7 percent of the more than 73,000 death certificates filed were amended - some simply fixed for misspelled names, incorrect dates, or updated causes of death. The department does not track how many times a manner of death has been amended.

The Sheridans' case now hinges on the expert opinion, including that of nationally known pathologist Michael Baden, whom the family hired days after the deaths to do an independent autopsy on John Sheridan.

Baden, in an affidavit filed with the medical examiner and attorney general, contradicts the findings of the state's pathologist, Eddy Lilavois.

Baden said John Sheridan's death was more indicative of a homicide than a suicide, partly because investigators never found the weapon that caused the five stab wounds.

Although the family has disclosed some of Baden's findings to reporters, Mark Sheridan has not authorized Baden to field questions from them. Sheridan also has not publicized Baden's affidavit.

"Our hope is that after reviewing the affidavit of Dr. Baden, they will come to the conclusion that our father's manner of death should be changed," said Mark Sheridan.

The deaths of the Sheridans, married for 47 years, shocked those within the elite social and political circles where the two were well-known. John Sheridan served as transportation secretary under Gov. Thomas H. Kean. Joyce Sheridan was a retired schoolteacher with the South Brunswick School District.

Mark Sheridan has said he wants the death certificate changed to restore his father's reputation. The family's efforts, he said, are not motivated by insurance, nearly all of which has been paid out.

In May, the family filed to change the death certificate with the state Appellate Division, which dismissed the case. In July, the Sheridans refiled to remand the case to Superior Court.

On Sept. 28 - exactly a year after the deaths - Appellate Judges Carmen H. Alvarez and Harry G. Carroll ruled that a formal application must first be made to the medical examiner with "substantiating documentary proof."

Had the family provided "an affidavit from Baden setting forth his medical findings and conclusions, and expressly stating his disagreements with the statements on the death certificate, the information that was before the agency would be clear," Alvarez wrote in an opinion.

On Dec. 17, the family filed the petition and supporting documentation.

Baden was hired days after the deaths as local law enforcement suggested a murder-suicide, Sheridan said. Investigators found no proof of domestic dispute, but still ruled the death a suicide to cover up the incompetence of county investigators and the medical examiner, Sheridan has said.

Jack Bennett, a spokesman for Somerset County Prosecutor Geoffrey Soriano, emailed "no comment" to the Inquirer when asked about the Sheridans' allegations.

Baden has suggested that John Sheridan's wounds are indicative of an attack. The prosecutor has denied the family access to the full investigative file. Mark Sheridan said he is asking to change the cause of death to undetermined because he does not believe authorities properly investigated or collected enough evidence to prove homicide.

In 2014, Baden told the family and authorities that investigators never recovered the weapon that caused Sheridan's five deep wounds, which he said was highly unusual for a suicide.

The death certificate listed cause of death as "self-inflicted injuries." One wound nicked the jugular. Two of the Sheridans' kitchen knives were recovered in the bedroom, including the one that killed Joyce Sheridan, puncturing her aorta. Lilavois agreed with Baden that neither knife caused John Sheridan's injuries because the blades were too wide to cause his narrow wounds.

Alvarez wrote in the September opinion that superficial and hesitation wounds are suggestive of suicide, while deep thrust wounds are indicative of a violent attack.

"Similarly, if the medical examiner concluded the wounds were caused by a deep thrust from a weapon that was not found at the scene, it required little speculation to conclude the death was a homicide," the judge wrote.

Soriano noted in his March 27 news release that melted metal was found in the couple's bedroom. Experts unrelated to the case, interviewed by the Inquirer in October, said that it was unlikely a knife would melt, and that John Sheridan's death was more likely a homicide than suicide.

Mark Sheridan, who had been on Gov. Christie's transition team, was counsel for the state GOP and stepped down last year because, he said, the government he believed in had failed his family.

John J. Hoffman, the acting attorney general, denied the family's request to take over the investigation. Hoffman announced Thursday that he was resigning to serve as senior vice president and general counsel at Rutgers University.

New Jersey has been without a statewide medical examiner since 2009, when Victor Weedn resigned. He wrote to Gov. Jon S. Corzine that the state agency was underfunded and understaffed.

The state's medical examiners also have been criticized by some law enforcement officers, child protection advocates, and others - including the Sheridans - who say the system is run poorly.

In June, Christie appointed Andrew Falzon as acting medical examiner, but he has yet to be confirmed by the Senate.

In October, Soriano's term as prosecutor expired. Appointed in 2010, Soriano remains in office, which is not unusual. The governor's office has not said whether he will be reappointed.

"We generally do not comment on the nominations and appointments process until a public announcement is made on a given position," Kevin Roberts, a spokesman for the governor's office, wrote in an email when asked about Soriano and Falzon.

Falzon did not return calls seeking comment about the Sheridan case.

Peter Aseltine, an attorney general's spokesman, said in an email that all information from the Medical Examiner's Office must go through his office.

The Attorney General's Office has denied an Inquirer request for a copy of the petition to change John Sheridan's manner of death.

"We do not have any comment and are not providing those documents," Aseltine wrote, adding, "We do not believe it would be appropriate to release those documents."

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