AUBURN – A breathless Daniel Roberts was heard on tape in court Monday telling a police dispatcher that his ex-girlfriend had just been shot.

Roberts rested his chin on his hands and sniffed as he listened to himself on the garbled recording played for an Androscoggin County Superior Court jury.

“I didn’t know she had the gun,” Roberts could be heard telling the dispatcher. That gun, a silver-colored revolver, belonged to Roberts. He has claimed Melissa Mendoza took it from his home when she was staying there during the weekend on a visit with the couple’s 2-year-old daughter shortly before the shooting.

“She is bleeding, right,” he said on the tape. There was a single bullet wound, he said.

The female dispatcher told Roberts to calm down as she quizzed him about the scene of the shooting.

“Leave everything where it is. Don’t touch anything, OK?” she said.

On trial for murder, Roberts, 37, has admitted that he shot dead Mendoza, 29, with a .38-caliber revolver in the back of the head when she came to his Sabattus home early in the morning on Aug. 15, 2005. He called 911 after the shooting.

Defense lawyers played the tape Monday during cross-examination of a detective to bolster Roberts’ claim of self-defense.

Roberts has said Mendoza pointed the silver gun at him threatening to shoot him, their daughter, Savanna, and herself. The couple was embroiled in a custody dispute. Police said they found the gun near her body, which was slumped on the floor just inside the garage door at Roberts’ home.

A firearms expert testified Monday via a videotaped deposition, saying the silver gun was never fired. Maine State Police Crime Lab specialist Joseph Roy Gallant said he looked at the gun under a microscope and didn’t find any marks to indicate it had been dropped on the concrete floor of the garage.

Another crime lab expert testified that the door from the driveway into the garage tested positive for lead vapors.

“That suggests to me a gun was fired in that location,” said Kimberly Stevens. A witness last week said it was likely Roberts was standing behind Mendoza near that door when he shot her in the back of the head.

Prosecutors have said Mendoza had taken only a couple of steps into garage when she was killed.

Deputy Attorney General William Stokes played messages from the cell phone of Stacey Robitaille left by Mendoza just hours before she was killed. Robitaille served as Savanna’s baby-sitter and supervisor at Roberts’ home the weekend Mendoza spent there.

On three voice mail recordings, an angry Mendoza is heard chastising Robitaille for lying to Roberts about claims that Mendoza had stolen money from Roberts’ home and neglected Savanna during the weekend visit.

“If you’re lying to Dan, you need to fess up,” Mendoza said in her message.

Robitaille, who started dating Roberts the month after he shot Mendoza, testified Monday that she never told Roberts that Mendoza had stolen money from his home. She also said she never used the word “neglectful” in describing Mendoza’s actions to Roberts.

After getting Mendoza’s first message, Robitaille said she called Roberts to say Mendoza had made the accusations.

The defense has said Mendoza had an opportunity that weekend to slip the silver gun from its hiding place between Roberts’ blue jeans stacked in his bedroom closet. Robitaille said she inspected the entire house when Mendoza arrived, at her invitation, but there were times during the weekend that Mendoza was alone in Roberts’ bedroom.

A different recording played in the courtroom Monday featured Mendoza during her departure from Savanna. During the emotional parting, Savanna can be heard wailing for her mother and Mendoza consoling her daughter, telling her she would see her soon.

Prosecutors are expected to wrap up their case soon in the trial that has lasted a week so far. Justice Joyce Wheeler said there was a chance a predicted snowstorm could postpone the trial on Wednesday.