PORTLAND – Maine’s highest court has denied the appeal of a Sabattus man who was convicted of murder for shooting his ex-girlfriend in the head while the two were in the midst of a bitter custody battle over their 2-year-old daughter.

Daniel Roberts never denied that he shot Melissa Mendoza in the garage of his home on Aug. 15, 2005, but maintained that the killing was in self-defense because she was armed with a loaded weapon and planned to either kidnap their daughter, Savanna, or kill him and the girl.

The Maine Supreme Judicial Court rejected Roberts’ arguments that the trial judge erred in admitting or excluding certain evidence and gave erroneous jury instructions. The justices also brushed aside the contention that the prosecution engaged in misconduct during its rebuttal closing argument by impermissibly referring to the defendant’s decision not to take the witness stand.

Roberts, 38, is serving a 55-year prison sentence.

In their unanimous ruling Tuesday, the justices upheld the admission of a protection from abuse affidavit filed by the victim days before the shooting. The court also found that the trial judge acted properly in admitting evidence of vandalism to Mendoza’s vehicle and that of a court-appointed visitation supervisor as well as two photographs showing Mendoza and her daughter kissing and smiling.

Roberts had claimed the photos were prejudicial because they would likely elicit an improper emotional response from jurors. The supreme court downplayed that argument, noting that other evidence at the trial established the caring mother-daughter relationship.

The justices also upheld the exclusion of defense testimony by two witnesses who were prepared to support testimony of longtime Roberts friend Jaime Bolduc that Mendoza stated shortly before her death that she would have shot Roberts if she had a gun. The state suggested that Bolduc made up the statement to protect Roberts.

The testimony was excluded because Bolduc repeated the statement to them only after Mendoza was shot and the motive to falsify arose, the court said.

At issue in the jury instruction was whether the judge should have said the state had to prove Roberts knew Mendoza was not about to use deadly force or kidnap her daughter rather than Roberts did not believe Mendoza was about to commit those acts.

The court concluded the jury instruction did not impermissibly lower the mental-state element that applies to the requirement that a defendant must have acted intentionally or knowingly in order to be convicted of murder.

In rejecting the prosecutorial misconduct claim, the court found that the state’s rebuttal argument was a proper comment on evidence presented to the jury and did not impermissibly refer to the defendant’s Fifth Amendment right not to testify.