Kansas City, Mo. ? Prosecutors using DNA evidence have charged a man already imprisoned for murder with two other killings.

Prosecutors announced Friday they charged Clifton L. Ray Jr., 44, on Thursday with two counts of first-degree murder. The victims were identified as Deborah D. Taylor, 27, who was found strangled in December 1987 in a vacant lot; and Joycie A. Flowers, age unknown, who was found strangled in May 1990 in a vacant field.

Ray was transferred Thursday to Jackson County from the Crossroads Correctional Center in Cameron, where he was serving a prison sentence for the 1994 strangulation death of Bobby J. Robertson, 68. He was due to be paroled June 27.

“And today he is currently in the Jackson County Jail with two additional charges,” Jackson County Prosecutor Mike Sanders said. “I don’t think that is something Mr. Ray was anticipating.”

Ray made his first court appearance Friday afternoon. The judge entered a plea of not guilty on his behalf. His next court appearance will be July 12.

John Oldham, a public defender who appeared with Ray at the hearing, declined to comment.

Ray was charged as a result of the same probe into a backlog of unsolved cases that led authorities in April to charge Lorenzo J. Gilyard with strangling a dozen women — all but one prostitutes — between 1977 and 1993. Gilyard pleaded not guilty last month at his arraignment.

A federal grant allowed authorities in crime labs to test evidence from old cases using the latest DNA technology.

Sanders said testing of semen left at the 1987 and 1990 crime scenes helped police connect Ray to the Taylor killing in December and the Flowers’ killing in March. Sanders said the odds that the DNA found at the crime scenes was not that of Ray was one in 470 quadrillion.

According to court records, Ray told authorities he didn’t know either victim and wasn’t involved in their deaths when he was interviewed last month. He also told authorities that he had “done a lot of bad things in his life, but he has made his peace with God, and God has forgiven him,” the probable cause statement said.

Sanders said his office planned to announce in the next three to five weeks whether it would seek the death penalty against Gilyard and Ray.

“We are not calling Mr. Ray a serial killer. But what we will say is the FBI standard for delineating someone as a serial killer is three or more homicides at unrelated times with unrelated victims,” Sanders said. “This, if that is the case and he is convicted, he would certainly meet the definition a serial killer.”