A Somerset County, N.J., judge ruled Wednesday that the search of Matthew Sheridan's Jeep on the day his parents died was unconstitutional, barring the state from using any evidence collected in the search, including cocaine.

Sheridan, a son of the late Cooper Health System CEO John P. Sheridan Jr. and his wife, Joyce, was arrested on drug charges after authorities searched his vehicle and found a small amount of cocaine, baggies, and a scale in 2014.

Although investigators obtained a warrant to search the SUV, Superior Court Judge Yolanda Ciccone told attorneys there was no probable cause to justify the search, making it unconstitutional.

At the time, police were investigating the deaths of John Sheridan, 72, and his wife, 69, a retired schoolteacher, who were stabbed and found dead after the master bedroom in their Montgomery Township home had been set on fire on Sept. 28, 2014. Matthew Sheridan had been living with his parents.

Authorities said early in the investigation that the couple's four sons were not suspects in the deaths, and that all had alibis that put them in other locations. Matthew Sheridan had been on a fishing trip in Connecticut. He returned early after a neighbor called him about the fire trucks at his home.

All of the couple's sons agreed to be interviewed without attorneys present because they were told they were not suspects in their parents' deaths, Mark Sheridan has said.

However, according to a transcript of a telephone conference between Somerset officials and the judge who approved the warrant, investigators wanted to search the Jeep for evidence related to the couple's death. Evidence they said they were looking for included knives, matches, accelerants, and blood.

Authorities did not say why they thought such evidence would be in Matthew Sheridan's SUV.

Mark Sheridan, a lawyer and Matthew's twin, has alleged the prosecution of his brother was retaliation for questioning the way the death investigation was handled.

The deaths were ruled murder-suicide. The family has criticized the county Prosecutor's Office, alleging that investigators botched the case. The sons allege that authorities ignored evidence that suggests both parents were murdered, and instead blamed John Sheridan as a way to cover up their incompetence.

Matthew Sheridan's attorney, Henry Klingeman, argued that he and the Sheridans were told his client would not be prosecuted on the drug charge if he cooperated with the death investigation.

In 2014, authorities confirmed that Matthew Sheridan had been arrested, but told the Inquirer he had not been charged. In 2015, the Middlesex County Prosecutor's Office was asked to handle the case, and this year indicted Sheridan on the drug charge.

Jack Bennett, a spokesman for the Prosecutor's Office, referred questions to the Middlesex Prosecutor's Office. James O'Neill, a spokesman for the Middlesex office, said his office would not comment on the case. Matthew Sheridan declined to comment.

Since the drugs and statements made by Matthew Sheridan can no longer be used as evidence, Klingeman said, he is not aware of any evidence that can be used to prosecute his client.

NJ.com quoted Middlesex Assistant Prosecutor Christopher L.C. Kuberiet as saying he was not sure whether his office would appeal, adding, "If evidence is suppressed, there is no case to proceed upon."

If the state does not appeal, charges would be dismissed, Klingeman said.

Klingeman said the case has taken an emotional and financial toll on his client. Matthew Sheridan lost his job as a financial adviser after the arrest.

"It's hard to imagine how much worse things could be for him after his parents were killed in such a horrific way," Klingeman said. "This case was weighing on him."

856-779-3838 @BBBoyer