PASADENA, Calif. -- A man linked by newly developed DNA technology to the May 1987 slaying of a 72-year-old Pasadena woman in a board-and-care home pleaded no contest on Monday to second-degree murder.

Pasadena Superior Court Judge Laura Priver immediately sentenced Robert Tillman, 56, to 15 years to life in state prison.

Under the plea deal, a special circumstance allegation that Mary Frances Drew was murdered during the commission of a rape was stricken, according to Sandi Gibbons of the District Attorney's Office.

"We felt that this is the best resolution of the case based on the fact that it's a 20-year-old case," Gibbons said. "In all likelihood, Mr. Tillman will spend the remainder of his life in prison."

Tillman has been jailed since being arrested last Sept. 6 by Pasadena police in connection with Drew's slaying.

The victim's body was found on May 6, 1987, in the board-and-care home where she lived in the 1100 block of North Los Robles Avenue. Tillman was considered a suspect at the time, but detectives had insufficient evidence to file a case against him, Pasadena police Lt. John Dewar said.

Last July, the Pasadena Police Department created an Unsolved Homicide Case unit to review more than 100 unsolved murders. The Drew case marked the first arrest stemming from those efforts.

Dewar said that DNA evidence collected from the Drew case was sent to a crime lab, and the murder charge was filed after Tillman's DNA was found in a sample from the evidence.