A New Jersey appellate court won't vacate the guilty plea of a man who killed his mother when he was a teen because she took away his car keys.

Victor Muglia had argued that his public defender should have raised the defense of diminished capacity. The Piscataway man claimed that would have kept his confession to police from being used against him, meaning he would have been acquitted or convicted of a lesser offense.

But the appellate court rejected that argument Tuesday, finding Muglia didn't provide any evidence that he suffered from diminished capacity when he committed the murder in March 2008.

Muglia was nearing his 18th birthday when he hit his mother on the head and back with a crowbar in their home. He was tried as an adult.

Now 28 years old, he is scheduled to be released from prison in 2040.