AUBURN – Closing arguments are expected Monday in the murder trial of a Sabattus man charged with fatally shooting his ex-girlfriend in the back of the head during a dispute over custody of their 2-year-old daughter.

Both the defense and prosecutors rested their cases Friday in the trial of Daniel Roberts, 37, who is charged with murdering Melissa Mendoza in his garage shortly before 1 a.m. on Aug. 15, 2005.

Roberts did not take the witness stand in his defense. His attorney, Leonard Sharon, said jurors heard his voice in a tape of a 911 call he made to police after the shooting.

“I think the jury’s heard everything they need to hear,” he said.

Roberts has admitted shooting Mendoza, who was 29, but claims he did so in self-defense when she threatened him with a gun he said she stole from him. Prosecutors claimed Roberts shot Mendoza and then planted the gun by her side to make it look like she was armed.

On Friday, a crime scene expert testified for the defense in an attempt to rebut a state forensics expert who testified that Melissa Mendoza probably wasn’t carrying a gun when she entered Roberts’ home because her hands were already full with a handbag and a soda bottle.

Peter DeForest, a professor at the John Jay College of Criminal Justice in New York City, said the evidence wasn’t strong enough to say what Mendoza was doing when she was shot.

DeForest also said it is possible Mendoza touched the gun found by her side without leaving DNA behind. Prosecutors have said the gun did not have her fingerprints or DNA on it.

“The absence of evidence is not evidence of absence,” DeForest said.

Mendoza and Roberts had shared custody of their daughter, Savanna, who was placed with each parent for six months of the year on an alternating basis.

Roberts, a former president of the Maine chapter of the Hells Angels motorcycle club, has been in jail since his indictment in December 2005.