SOMERVILLE — A veteran detective involved in investigating the deaths of a prominent hospital executive and his wife now says the Somerset County Prosecutor’s Office botched the probe by mishandling and destroying evidence.

The explosive allegations threaten to cast new doubt on the office’s conclusion that the 2014 case was a murder-suicide.

Officials concluded last year that 72-year-old John Sheridan, the CEO of Cooper Health System, murdered his wife, Joyce, 69, by stabbing her in their Montgomery home’s bedroom, then set the room on fire and committed suicide by stabbing himself five times in his neck and chest. The weapon that caused John Sheridan's wounds was never recovered.

The Sheridans' sons have publicly disputed the office’s findings and the couple’s powerful connections have backed the sons’ ongoing campaign to reopen the investigation.

It was common knowledge among detectives... that the Sheridan evidence was improperly collected, improperly preserved and subsequently destroyed.

Gov. Chris Christie announced in February that Geoffrey Soriano would not continue as Somerset’s prosecutor following his expired term, later saying that he had “lost confidence” in Soriano. Christie’s announcement followed a day after three former governors joined about 200 other prominent state residents on a letter calling for a new investigation.

For the first time, however, skeptics of the investigation are bolstered by someone from the Prosecutor's Office.

“It was common knowledge among detectives assigned to the Forensic Unit that the Sheridan evidence was improperly collected, improperly preserved and subsequently destroyed,” according to the text of a whistleblower lawsuit filed last month by Somerset County Prosecutor’s Office Detective Jeffrey Scozzafava. Details of the lawsuit are being reported by New Jersey 101.5 for the first time.

Scozzafava says that officials with little or no experience in forensics were put in charge of the Forensics Unit and that officials retaliated against him when he pointed out errors and concerns he had with the Sheridan investigation and other cases.

I hope this will help get us some answers. ... This is criminal.

The Prosecutor’s Office could not be reached for comment late Wednesday. A spokesman for the state Attorney General’s Office said officials there were aware of Scozzafava’s allegations but declined to comment further.

Mark Sheridan, who speaks on behalf of his family, said Wednesday that the lawsuit shows that Christie was right to replace Soriano.

“I hope it will help get us some answers,” he said. “This is what we’ve been saying from day one about what’s going on in this office. It’s criminal.”

Scozzafava, who began working with the office in 2007 after retiring as supervisor of crime-scene detectives with the State Police, alleges:

Evidence from the Sheridan bedroom, including large pieces of charred bedding, were left lying exposed for months on the vehicle bay floor and stored in an open bag in the fingerprint lab.

Blood collection swabs were “improperly packaged” by a forensic technician.

Evidence envelopes were “shoddily taped, leaving open gaps that created the potential for contamination.”

Capt. Lee Niles told an assistant prosecutor that investigators had searched for fingerprints using what he called a “flashlight technique” even though no such technique existed "and was an obvious excuse for nonfeasance during scene processing.”

Perhaps the most shocking charge is Scozzafava's claim that in early 2015 he witnessed Niles take the improperly stored bedroom evidence and throw it into a dumpster in the office's parking lot.

The lawsuit does not say why Niles did this. Scozzafava's attorney, David Zatuchni, of Lambertville, declined to comment for this report.

Sheridan said Wednesday that he had been aware that the investigation had failed to turn up fingerprints and that the results of the DNA testing suggested that the evidence may have been contaminated.

“But we had no idea that anybody destroyed evidence or that the contamination was the result of malfeasance or neglect," he said.

“The attorney general should be all over this,” he said, adding that if even if just some of Scozzafava’s allegations are true, it should lead to criminal charges against Niles.

The Sheridan family has petitioned to have the state Medical Examiner's Office overturn the ruling that John Sheridan killed his wife. They submitted an opinion from their own pathologist, Michael Baden, who conducted his own autopsy and concluded that John Sheridan's death appears to be a homicide, not a suicide.

Mark Sheridan said state officials still had not responded after six months and the family may have to go back to court.

"The review of Dr. Baden's affidavit has take longer than the entire investigation by the Somer County's Prosecutor's Office," he said. "It's pathetic."

Scozzafava still works for the Prosecutor's Office and claims he was reassigned to the Fugitive Unit as retaliation. His 12-page lawsuit seeks an unspecified amount of damages under the state's Conscientious Employee Protection Act.

Sergio Bichao is deputy digital editor at New Jersey 101.5. Send him news tips: Call 609-438-1015 or email sergio.bichao@townsquaremedia.com.