Pennsylvania man confesses to 30-year-old killing. Police say he is a suspect in more deaths

(CNN) — A Pennsylvania man serving life in prison for the grisly murder of his wife and stepdaughter has confessed to another killing, resolving a cold case from the 1980s, officials said Thursday.

Several other cases are under review, they said.

Regis Brown, 59, admitted to killing Bryce Kenneth Tompkins, 45, whose body was found by hunters partially submerged in Neshannock Creek in Lawrence County in December 1988, authorities said. He told police that Tompkins was killed because he witnessed a burglary.

Brown was sentenced last month in the March deaths of his wife, Michelle Brown, 53, and his stepdaughter, Tammy Greenawalt, 35.

Eric Hackwelder, the attorney who represented Brown during the double homicide case, said he may be retained by Brown to represent him at his October arraignment related to the killing of Tompkins.

“It is surprising,” Hackwelder said. “He made a complete confession initially and he was very cooperative with authorities. And it’s my understanding that he’s very cooperative at this point as well.”

Trooper Joseph Vascetti, criminal investigator for the Pennsylvania State Police, said he believes Brown confessed because he’s already serving a life sentence, and had nothing to gain or lose by continuing to keep the secret.

Brown is considered a suspect in as many as eight other cold cases, Vascetti told CNN. Altogether, he said, Brown may have information about as many as 15 other killings.

Hackwelder said he had no knowledge of other deaths and plans to speak with his client on Friday.

In the Tompkins case, Brown was charged with one count of criminal homicide, two counts of aggravated assault, and one count of intimidation of a witness.

Tompkins was in the wrong place at the wrong time in December 1988, Vascetti said. Brown and another man finished had burglarizing a home in New Castle when they spotted Tompkins walking outside. Brown and the second man planned to kill Tompkins because they believed he would tell police of the burglary, Vascetti said in court papers. One item stolen was a .38-caliber Smith and Wesson revolver.

According to an affidavit, a few days later, Brown and the second man confronted Tompkins, who they knew would go for walks at night. Brown admitted to firing two shots in his back with the handgun taken in the burglary, the affidavit says.

“He was minding his own business,” Vascetti said.

Brown was identified as a suspect for years but never admitted to the killing, Vascetti said. Brown has so far only admitted to the three homicides, but more information on other killings may be on the way, officials said.

“He did provide information that the Pennsylvania state police are investigating, and it is related to other homicides,” said Lawrence County District Attorney Joshua Lamancusa at a news conference on Thursday. “Those cases are pending right now so we can’t get into the specifics of what exactly he said and which cases we are referring to, but yes he did provide other information related to other homicides.”

In March, Brown had gotten into a heated argument with his stepdaughter hours before he stabbed and beat her to death, Vascetti said. And once his wife got home from work, Brown bludgeoned her to death.

Brown was sentenced to life in prison for the first-degree murder of his wife and was given 40 years for his stepdaughter’s death, Hackwelder said.