In this Thursday, April 19, 2018 file photo, Freddie Joe Lawrence, right, one of two men whose convictions were overturned for a 1994 murder, speaks at a press conference with Montana Innocence Project attorneys Toby Cook, left, and Larry Jent in Missoula, Mont. Lawrence and co-defendant Paul Jenkins were convicted in the 1994 death of Donna Meagher, whose body was found west of Helena. Recent DNA tests on a rope found at the murder scene matched another man, a convicted killer. On Friday, June 1, 2018, District Judge Kathy Seeley of Helena dismissed the charges against Lawrence and Jenkins. The state is investigating David Wayne Nelson as a suspect in Meagher's death. (Photo: Tom Bauer/The Missoulian via AP, File)

Two men who served 23 years in Montana prisons for a 1995 robbery and homicide were released in April. The pair are now effectively exonerated, after the state moved to drop the charges on Friday, and the judge approved.

Paul Kenneth Jenkins and Fred Joe Lawrence were serving life sentences for the murder of Donna Meagher, a bartender, until the DNA mixture analysis on a bloody rope used to bind her.

The mixture yielded a male’s DNA—which was later identified through the national CODIS database as that of David Wayne Nelson, a man who is already in prison for a separate double homicide.

The DNA analysis was conducted by Greg Hampikian, of Boise State University, using a Bureau of Justice Assistance grant. The tool used in the mixture analysis was TrueAllele, a probabilistic genotyping software program that has been used in prosecutions and exonerations alike.

The complex mixture analysis determined that the male DNA on the part of the rope that was not stained with blood made up 60 percent of the total DNA. The profile was independently derived by STR analysis through processing by Bode Cellmark.

Nelson remains under investigation for his apparent DNA connection to the 1995 crime scene, the Montana Attorney General's Office told Forensic Magazine Tuesday.