AUBURN – Melissa Mendoza told a friend hours before she was shot to death that she might do “something crazy or stupid” if she didn’t hear from Daniel Roberts right away, a witness testified Thursday in Androscoggin County Superior Court.

Roberts has told police his ex-girlfriend came to his Sabattus home, pointed a gun at him and told him she would shoot her 2-year-old daughter, Roberts, then herself. He has said he shot her in the back of the head in self-defense.

She died of a single shot from a .38-caliber handgun from about two feet away, state police said.

Prosecutors revealed the gun found next to her body bore neither Mendoza’s fingerprints nor her DNA.

Eric Johnson of California, who once was Roberts’ roommate, took the stand for the defense at Roberts’ murder trial. Johnson said he got a flurry of calls from Mendoza the night before she was killed.

Johnson said he often served as mediator between the estranged couple. They were embroiled in a custody dispute over their toddler, Savanna.

Roberts, 37, shot Mendoza, 29, shortly after 1 a.m., Monday, Aug. 15, 2005. Hours earlier, on Sunday night, Johnson was in California entertaining guests and beginning a barbecue dinner.

He said Mendoza started phoning him to complain about Roberts, custody of Savanna and Maine courts.

Johnson said he tried to calm Mendoza. He said she needed to relax and let the courts deal with it.

Mendoza insisted that Roberts call her. “She said she needed to talk to Dan right (expletive) now,” Johnson said. Mendoza told Johnson that if Roberts didn’t call her, “she might have to do something crazy or stupid.”

As the night wore on, Mendoza’s speech became more erratic and slurred, her tone more insistent, Johnson said.

Johnson later called Roberts, leaving the message: “Dan, call me; Melissa has really gone off the hook.”

He said he eventually talked to Roberts, who told Johnson he wouldn’t talk to Mendoza because she had a protection from abuse order forbidding it. He suggested Johnson not talk to Mendoza either.

Mendoza tried calling Johnson again several times, but he had decided to stop answering her calls, he said.

Deputy Attorney General William Stokes showed Johnson a transcript of his testimony from a 2005 bail hearing and noted inconsistencies with his testimony given Thursday.

Johnson said he had been confused about the timing of the phone calls in his earlier testimony due to the different time zones between Maine and California. Stokes also questioned why Johnson would wait more than two hours before telling Roberts that Mendoza talked about doing something “crazy or stupid.”

Mendoza didn’t tell Johnson anything about wanting to hurt her baby or having a gun, he said on cross-examination.

When Johnson talked to Roberts, he didn’t say anything about Mendoza having taken his gun, Johnson said.

Roberts told police at the time of the shooting that he thought Mendoza had taken a silver-colored gun from his bedroom closet that weekend. He said he noticed Sunday evening that it was missing from its hiding place between blue jeans stacked on a shelf. That’s the same gun police found next to Mendoza’s body.

Two paramedics testified Thursday, saying they never touched that gun, but did see it lying next to the wall in the garage near Mendoza’s feet.

Roberts’ father, first on the scene, testified on Wednesday that both her body and the gun had been moved after police arrived.

Defense attorney Leonard Sharon said he expected to rest his case today. He said he plans to play for the jury an interview with a forensics expert recorded Thursday. Peter DeForest, a college professor, would rebut testimony given last week by a crime scene reconstruction expert called by prosecutors, Sharon said.

DeForest, an adviser to the Goldman family in the civil suit against O.J. Simpson, is expected to testify that the conclusions drawn by the prosecutor’s witness, Tom Bevel, “have no basis in science whatsoever,” Sharon said.