A southern Missouri man who spent 12 years in prison for murder before the Missouri Supreme Court overturned his conviction won't be retried in the killing of his live-in girlfriend.

SALEM — A southern Missouri man who spent 12 years in prison for murder before the Missouri Supreme Court overturned his conviction won't be retried in the killing of his live-in girlfriend.

The Dent County prosecutor filed a motion Friday dropping the murder charge against Donald "Doc" Nash, who has long insisted he didn't kill Judy Lynn Spencer. The 21-year-old Salem hospital receptionist was strangled with her shoelace and then shot in 1982. But Nash, a retired union foreman, wasn't convicted of murder until 2009 after law enforcement reopened the cold case.

The prosecution relied primarily on minute traces of his DNA that were found beneath Spencer's fingernails. Nash's lawyers argue that this is typical for couples living together. 

Nash was released in July after the Missouri Supreme Court decided to vacate Nash's conviction. One issue was that new testing of the shoestring used to strangle Spencer revealed the DNA profiles of two males, neither of whom were Nash. 

That decision left the case in the hands of county prosecutor Andrew Curley, who wasn't in office in 2009. He said in a statement that he wasn't retrying the case because the new evidence creates reasonable doubt.

"'I hope and pray," he added, "that justice can be delivered for Judy and her family in the future for this tragic loss of life.'"