RUTLAND, Vt. (AP) — Police are investigating whether an upstate New York man is linked to cold case killings in New York after he was recently charged with the 1989 stabbing deaths of his in-laws in Vermont.

Michael Louise was arraigned in Vermont Superior Court in Rutland on Friday, two days after he was returned to Vermont from New York to answer charges in the deaths of George Peacock, 76, and Catherine Peacock, 73. Louise was charged after modern DNA techniques linked him to the crime in Danby.

Louise pleaded not guilty at the arraignment.

The prosecutor mentioned Louise’s possible links to other cases as he argued that the Syracuse, New York-area resident should be held without bail.

New York State Police confirmed later Friday that investigators in central New York are looking into possible links between Louise and several cold case homicides in the region. A spokesman did not identify which cases or provide details.

Louise entered the pleas and then was ordered held without bail, said Vermont State Police spokesperson Adam Silverman, who monitored the hearing remotely.

Louise, 79, who was married to one of the Peacocks’ daughters, was identified as a suspect about two weeks after the couple was found dead in their Danby home in September 1989. Investigators at the time developed circumstantial evidence tying Louise to the killings, but there was not enough to charge him, police said in an affidavit filed in the case.

Louise told conflicting stories about whether he had traveled to Vermont from his home in Liverpool, New York, on Sept. 13, 1989, the day the Peacocks were believed to have been killed. Their bodies were discovered Sept. 17 after neighbors went to check on the couple.

When Louise’s car was searched by the New York State Police on Oct. 6, 1989, investigators discovered what was described as a small blood deposit, later determined to be human, on the driver’s side floor mat. At the time, the blood deposit was not large enough to be typed.

The blood was subjected to DNA testing in 2000 by the Vermont forensic lab, but current testing is more sensitive. Retesting in October 2020 found that a portion of it matched a sample taken from George Peacock.

Police have not publicly suggested a motive for the killings.