BANGOR — DNA profiles matching samples taken from Robert Burton were found in sperm cells on swabs taken from the cervix of homicide victim Stephanie Gebo, a medical laboratory specialist testified Thursday during the fourth day of Burton’s murder trial.

Defense and prosecuting attorneys spent most of the day offering forensic evidence from Burton, who is on trial for murder, and from Gebo, the victim, who was killed in June 2015 in the town of Parkman, some 35 miles north of Skowhegan.

Brandi Caron, a forensic chemist with the state crime lab, testified about the DNA findings from cervical and vaginal swabs, noting that sperm cells could be detected days after intercourse. The DNA profiles that match Burton’s samples were also found on a knife handle found at Gebo’s house where the shooting took place and in blood on Burton’s shirt and in his truck.

Burton’s fingerprints were found on an exterior window at Gebo’s home, and duct tape found ripped on Gebo’s body matched duct tape found on Burton’s shirt and in his truck. Prosecutors have said the lock on the window in Gebo’s bedroom appears to have been rigged to allow entry from outside, though it appears to be locked shut.

The defense argues that the couple had consensual sex just days before the fatal shooting and is trying to convince the jury that Burton had been set up to be shot by Gebo as he entered her home on June 4, 2015, or early June 5. Police have said Burton, 40, was shot with Gebo’s 9 mm handgun through the upper torso before he turned the gun on her, shooting her three times and killing her.

He bled profusely before fleeing and was on the run for 68 days in rural Piscataquis County before turning himself in.

Terry Thurlow, a health worker who examined Burton at the Piscataquis County jail shortly after he turned himself in, testified that Burton had a gunshot wound that was a “flesh wound.”

Thurlow agreed that Burton appeared to be healthy and well nourished and ordered an x-ray of the area of the gunshot wound and found no bullet fragments and no broken bones.

“It was healing nicely,” Thurlow said of the entry wound near Burton’s shoulder. The back wound “wasn’t quite as healed,” he said.

Defense attorney Hunter Tzovarras spent considerable time Thursday on academic medical and scientific details concerning blood, semen and DNA, apparently trying to convince the jury of nine men and six women that Burton did not go to the house to kill Gebo. He argued that the scientific evidence showed Burton and Gebo had consensual sex in the days leading up to the shooting.

Tzovarras insisted that when Burton entered Gebo’s bedroom through a window, Gebo lifted a bed pillow and shot him through the pillow. The bullet ricocheted into the ceiling, where police found it lodged between the first and second floor of the house.

The pillow, with bullet holes and burnt powder, was produced as evidence.

The prosecution team of Assistant Attorneys General Donald Macomber and John Alsop is attempting to paint a picture of Burton as an obsessive, jealous man who suspected his former girlfriend had been cheating on him when he murdered her in June 2015 in Parkman. Burton’s defense team of Zachary Brandmeir and Tzovarras is countering that Burton acted in self-defense after Gebo shot him with a handgun she kept within reach in her bedroom.

Macomber has noted in open court that a self defense claim wouldn’t work if Burton had compelled Gebo to protect herself by shooting him.

Thursday’s testimony at the Penobscot Judicial Center in Bangor follows the testimony of retired Chief Medical Examiner Margaret Greenwald, who on Wednesday said that one of the three shots that killed Stephanie Gebo in her home in June 2015 probably was fired while the mother of two was already down on the floor of her bedroom in Parkman, bleeding from two other shots.

Greenwald, who conducted the autopsy on Gebo’s remains on June 7, 2015, found gunshot wounds to the lungs, spinal area and trachea and determined the death was a homicide. She also found what might be considered a defensive wound on Gebo’s hand and other cuts and bruises.

Under direct examination by Assistant Attorney General Donald Macomber, Greenwald said a bullet that police found that was embedded in the wooden floor under Gebo’s body was consistent with a shot having been fired while she was on the floor.

Greenwald said she also found bullet fragments in Gebo’s body during the autopsy, possibly accounting for the fact that four 9 mm shell casings were found by investigators, but only three bullets.

Burton led authorities on the longest manhunt in Maine history, 68 days, after Gebo’s body was discovered and police were called. He walked into the Piscataquis County Jail in Dover-Foxcroft on Aug. 11, 2015, and surrendered peacefully, saying he didn’t want to get shot by police.

Burton is charged with murder in the shooting death of Gebo, then 37, in the Parkman home they once shared in Piscataquis County. He has pleaded not guilty to the charge.

Gebo, a single mother of two, was shot to death with a pistol, according to police. She had broken up with Burton the previous weekend and was killed the day after Burton’s probation for a domestic violence conviction that had sent him to prison for 10 years ended.

Piscataquis County Sheriff John Goggin told WVII-TV in July 2015 that Burton had climbed in through the window. Goggin said Burton was wounded by Stephanie Gebo before he turned the gun on her.

“As he was climbing through the window that night, his would-be victim had a handgun and she shot at him,” Goggin said in the interview with the Bangor TV station. “He wasn’t armed at that time. She wounded him slightly, they got in a tussle over the gun, and he just lost it. He got the gun away from her and he shot her and he killed her.”

The gun has not been found.

Doug Harlow — 612-2367

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Twitter:@Doug_Harlow