A Caribou man who kicked and beat his supervisor at Tim Hortons and continued to serve customers as she was left to die in an employee bathroom was convicted of murder, gross sexual assault and robbery on Wednesday.

Christopher Shumway looked down as the judge rejected the defense claim that Shumway was not criminally responsible for Erin Sperrey's death because of mental problems.

Justice Allen Hunter acknowledged that Shumway had mental problems but said they were not severe enough to hinder his ability to recognize right from wrong.

Sperrey's mother, Johna Lovely, broke down in tears.

The mental state of Shumway was the key issue during the trial. The defense contended Shumway suffered from mental illness and sexual abuse, and the judge was told that Shumway binged on alcohol and drugs before the killing.

Two prosecutors told the judge that Shumway's mental and substance abuse problems didn't preclude him from knowing right from wrong.

Shumway, 20, continued to serve customers following the attack on Sperrey in the coffee shop's walk-in cooler and in the employee bathroom on Jan. 2, 2005.

Afterward, Shumway stuffed Sperrey's lifeless body in her car and drove south for 120 miles until he spun out on Interstate 95 in a snowstorm. He abandoned the body and the car, and hitched a ride to a Bangor motel, where he was arrested the next day.

At some point, Shumway allegedly sexually assaulted Sperrey.

Lawyers delivered their closing arguments on July 14, but Hunter wanted time to review what he described as "an incredible amount of evidence."

Hunter, who decided the case without a jury in Aroostook County Superior Court, weighed conflicting testimony about the degree of Shumway's mental problems. Among other things, Shumway suffered from post traumatic stress disorder after being sexually abused as a young boy before he moved to Maine, the defense said.

Defense lawyer Brad Macdonald said Shumway was thrown into a rage when Sperrey mentioned the incestuous sexual abuse during a confrontation.

The victim's family has said that Shumway had a crush on Sperrey and had asked her out on dates several times before he killed her. Witnesses said he also talked of stealing money to allow him to return to Massachusetts where he grew up.

More evaluations will be conducted on Shumway before he's sentenced. The process could take six to eight weeks, the judge said.