MEDFORD, Ore. (AP) -- A convicted bank robber has been found not guilty of criminal mistreatment in the death of his ex-girlfriend's 2-year-old boy.

Jackson County Judge Patricia Crain issued the ruling Wednesday at the end of Bruce Satterlee's two-day bench trial.

Autopsy photos displayed during the trial showed the bruised and battered body of 2-year-old Caleb Hearne. Medical testimony described acute trauma injuries to the toddler's liver and pancreas that ultimately caused his death on Feb. 22, 2007.

Crain blamed the Medford boy's death on the mother, Trisha Marie Torresan, who is serving a 3 1/2-year prison sentence after pleading guilty in March to criminally negligent homicide and criminal mistreatment.

Torresan, 26, testified for the state this week wearing prison clothes. During direct and cross examination, she denied causing Caleb's death, but acknowledged "smacking" the boy and "popping him in the face."

Crain criticized Torresan's rationalization of her guilty plea.

"The mother is a complete liar," the judge said.

Chief Deputy District Attorney Beth Heckert argued in closing that Satterlee, himself a father of two young children, admitted he was aware of Torresan's abuse.

"He told police, 'I had to go upstairs because she's going to hurt (Caleb),'" Heckert said. "He could have picked up the phone. He could have called someone. He clearly knows this is an unsafe environment."

Torresan and Satterlee met online in October 2006 and Satterlee moved into her place the following month. They broke up after Caleb's death.

"I know he regrets this entire relationship with Ms. Torresan," said Charles Kochlacs, Satterlee's defense attorney.

In her ruling, the judge said testimony showed Satterlee had tried to intercede with Torresan when she abused her son. Moreover, Satterlee could not have known the toddler had suffered injuries that would ultimately result in his death.

"And there is no allegation that he caused the injuries that turned up," Crain said.

Satterlee, 28, appeared before Crain in March after admitting he robbed a Shady Cove bank last November. He was sentenced to more than four years in prison.