The Associated Press reports that a California prosecutor has opposed DNA testing in a murder case from 1983. Prosecutors say previous testing proves the man on death row is the correct suspect, but defense attorneys say Kevin Cooper was framed by law enforcement.

Cooper, now 60 years old, is awaiting execution for his conviction in the 1983 case where four people were knifed to death. He had escaped from prison just east of Los Angeles two days before the murders. The victims of the 1983 Chino Hills hatchet and knife killings included Doug and Peggy Ryen, their daughter, age 10 and a neighbor boy, age 11.

The San Bernardino County District Attorney had agreed to new DNA testing in 2001 and 2002 of evidence selected by a DNA expert selected by Cooper. Those tests showed he was in the home at the time of the murders and smoked cigarettes in the Ryen’s station wagon. His blood and that of at least one victim was also found on a shirt on the side of the road nearby.

Cooper had his execution stayed in 2004 when an appellate court called for further review of scientific evidence. Another judge determined that Cooper was alone responsible for the murders.

A third round of DNA testing requested in 2011 was blocked by a San Diego judge.

A column in the New York Times sparked interest in the case last week, suggesting that Cooper was framed. The state’s governor is reviewing the most current clemency request by Cooper.

No one has been executed in California since 2006.

Defense attorney Norman Hile claims that more sensitive DNA testing would prove the 2004 testing framed his client. Those tests showed preservative in the blood sample as well as contamination with another person’s blood.

*Photo credit The Associated Press