AUBURN – The handgun Daniel Roberts said his ex-girlfriend pointed at him as she threatened to kill him and their daughter bore none of her fingerprints or any of her DNA.

The only DNA found on the gun matched Roberts, who owned the loaded weapon, expert witnesses testified Friday, the fifth day of Roberts’ murder trial in Androscoggin County Superior Court.

Roberts, 37, has admitted shooting Melissa Mendoza, 29, in his garage early on the morning of Aug. 15, 2005. He claimed Mendoza pointed a silver-colored .38-caliber revolver at him. She told him she planned to kill him, their 2-year-old daughter, Savanna, then herself, he said.

Police found Mendoza’s body slumped on the cold concrete of his garage floor near the driveway door, shot in the back of her head. The gun Roberts said she pointed at him was near her body before paramedics apparently kicked it as they tended to her at the scene.

A medical examiner calculated that Roberts likely stood near the door behind Mendoza when he shot her. The bullet struck her in the back of the head almost four inches from the top and slightly left of center. It punctured her skull, passed through her brain and exited the area of her left temple. The bullet struck the Sheetrock wall of the garage nearly eight feet from the floor, said Dr. Michael Ferenc, former deputy chief medical examiner in Maine.

Ferenc said he couldn’t determine how far Roberts was standing from Mendoza when he shot her because her thick black hair may have prevented gunpowder residue from making contact with her skin.

Deputy Attorney General William Stokes continued Friday to build his case against Roberts using testimony about crime scene evidence, including fingerprints, DNA, medical examination and photos.

A DNA expert from the Maine Crime Lab said the rubber grips from the silver-colored gun matched Roberts’ DNA on 10 points out of 13 for a 1-in-69 billion chance it could also match somebody else.

Stokes asked Jennifer Sabean whether Mendoza could, according to the DNA analysis, be excluded as someone who handled the gun. “Yes,” Sabean answered.

A state police detective, now retired, who collected evidence at the scene, said he took an empty gun holster from a hutch in Roberts’ Sabattus home.

Stokes later questioned a witness who testified he sold Roberts the silver-colored gun found near Mendoza’s body. He sold Roberts two guns, including the revolver Roberts used to kill Mendoza. Both guns were slipped into the holster in the courtroom, but the only one that fit the holster was the one Roberts said Mendoza brought with her to the garage that morning to meet him.

Defense attorney Leonard Sharon said after court adjourned that the lack of fingerprints and DNA on the silver-colored gun could be explained by the gun sliding across the concrete floor when it was kicked, coupled with its handling by crime scene investigators. Maine Crime Lab analysts who testified Friday said some evidence could possibly be lost that way.

Sharon said the empty holster that retired Maine State Police Detective Jeffrey Smith took from the hutch would be explained later in the trial when witnesses will testify that neither gun was kept in its holster.

Sharon has suggested that Mendoza could have taken the silver-colored gun from Roberts’ home the weekend before she was killed. She had been staying there during a supervised visit with their daughter.

A fingerprint from Roberts’ right index finger was found on the flat underside of the barrel of the gun he used to shoot Mendoza.

No usable fingerprints or DNA could be found on the shell casings of any of the bullets, including the one Roberts fired, the experts said.

Mendoza’s family members sat through the testimony Friday as they have every day of the week-long trial. Her mother, Mary, looked at the floor whenever enlarged photos of the crime scene showing her daughter were exhibited.

Mendoza’s uncle, Mac Garcia, read a statement on the courthouse steps during a lunch break.

“We know that justice will be served after all the testimony is heard. It has been very difficult for us, but we are here for justice and for our Missy, whom we don’t have anymore.” He said the family plans to sit through the entire trial, which Justice Joyce Wheeler said could last most of the month.