The GBI on Tuesday reopened a decades-old double murder case after new DNA evidence cast doubt on the conviction of the man who has served 20 years for the killings.

Brunswick District Attorney Jackie Johnson requested the investigation Tuesday after learning six weeks earlier of the DNA test, which points to a previous suspect in the 1985 murders of Harold and Thelma Swain. The couple was shot inside Rising Daughter Baptist Church in Camden County during a Bible study after a stranger walked in and got into a confrontation with Harold Swain, a deacon.

Attorneys for Dennis Perry, 58, who was convicted in 2003, conducted the test after reporting by The Atlanta Journal-Constitution uncovered problems with the alibi of former suspect Erik Sparre. Sparre, who had been dropped as a suspect in 1986 because of the alibi, allegedly told multiple people he killed the couple, according to police records and interviews conducted by the AJC.

» SPECIAL PRESENTATION: "The Imperfect Alibi"

» FULL COVERAGE: The Rising Daughter investigation

Perry’s attorneys say the DNA test now links Sparre to hairs found in a pair of glasses that were discovered near the bodies. Sparre has told the AJC he is innocent and has never been to the church.

DA Johnson’s office said it will use the GBI’s findings to decide how to respond to a motion for new trial Perry filed late last month. The DA’s request for the investigation to be reopened comes amid a firestorm surrounding her office over its handling of the Ahmaud Arbery shooting. Georgia Attorney General Chris Carr has asked both the U.S. Department of Justice and the GBI to investigate DA Johnson’s office.

Perry’s attorneys said the GBI investigation should’ve come much sooner.

“We are surprised and disappointed to learn that the District Attorney waited six weeks after we provided the DNA results to ask for this assistance,” the lawyers with the Georgia Innocence Project and the King & Spalding law firm said in a statement. “While we are heartened that the GBI is now investigating … Mr. Perry remains in prison for crimes he did not commit.”

» RELATED: New clues in old Georgia church murder

Sparre, 56, apparently learned for the first time about the DNA match earlier this month not from investigators but from the AJC in a phone call. “I don’t have any glasses missing,” he said before telling a reporter to leave him alone. He didn’t respond to a text Tuesday.

The renewed GBI investigation is the latest twist in a case that has confounded investigators and sowed division for 35 years. The news comes after Perry’s attorneys filed a motion for new trial, arguing Perry never would’ve been prosecuted if Sparre’s DNA had been available at the time of his trial. A DNA test before the trial showed Perry didn’t match the hairs found in the glasses’ hinge.

Perry was convicted largely on the testimony of his ex-girlfriend’s mother, who said Perry had told her he was going to kill Harold Swain because Swain had laughed in his face when Perry asked for money. The state didn’t tell the defense that the witness would be paid $12,000 in reward money for her testimony, according to Perry’s attorneys.

Five legal experts examined the DNA finding and the motion for new trial for the AJC. All five — including former Georgia Supreme Court Chief Justice Leah Ward Sears — said Perry should be freed unless the state has compelling evidence to refute the DNA results.

“I would let him go,” said Sears, who handled numerous such cases when she was on the high court. “DNA doesn’t lie.”

The test compared DNA taken from Sparre’s mother to DNA in the hairs found at the scene. The results show that the hairs in the glasses belonged to someone from Sparre’s maternal line, according to the motion for new trial. “The new DNA evidence is critically significant because it for the first time provides reliable forensic physical evidence linking a known suspect, Erik Sparre, to physical evidence at the crime scene,” the lawyers wrote.

The original lead investigators on the case, former Camden County Chief Deputy Butch Kennedy and retired GBI agent Joe Gregory, didn’t test Sparre’s DNA in 1986 because such testing was in its infancy. They investigated Sparre after his ex-wife’s family said they caught him on tape saying he killed the “two n——— in that church,” according to police records. The tape has gone missing, along with much other evidence in the case. The ex-wife, who said Sparre “hated blacks,” is dead. Emmett Head, the ex-wife’s brother who was on the phone with Sparre during the alleged confession, declined to comment. (Sparre also told his second ex-wife, Rhonda Tyson, he killed the couple, she told the AJC.)

In 1986, the investigators dropped Sparre as a suspect after a man claiming to be Sparre's boss called the GBI agent to say Sparre had been at work on the night of the murders. The AJC determined many details in the police document about the alibi could not be true.

The original investigators had also looked into Perry in 1988 after a dubious tip. They say they learned he lived in Jonesboro at the time of the murders. Perry had worked until the late afternoon on the day of the murders, which the detectives said would not have given him enough time get to the church by 8:45 p.m.

On Tuesday, Kennedy, the original lead investigator who has long believed Perry is innocent, said he was pleased by the GBI investigation.

“I’m really happy,” he said. “I’m proud as I can be somebody’s going to be looking at it.”