MARTINEZ, Calif. (KGO) -- A Walnut Creek police officer was in court Monday answering to a bizarre crime that occurred last month where he was suspected of beating a woman while wearing a ski mask.



Walnut Creek police officer Gregory Thompson, 54, pleaded no contest Monday to three felonies, including assault with intent to cause bodily harm and being armed with a gun at the time of the crime.



"To his credit, his admission of guilt will allow him to get on with his life," Contra Costa County Deputy District Attorney Barry Grove said.



Thompson was arrested Aug. 16 outside of his father's vacant home that was for sale in Richmond. He's suspected of brutally attacking a woman he thought was trying to break in.



"It appears he believed someone was trying to break into his father's home to seek shelter," Grove said. "With a ski mask on and gloves he beat her with a bat."



Investigators say the woman had simply run out of gas and was simply walking in the neighborhood when she was attacked. Her injuries were serious but not life threatening. Thompson is a 30 year veteran of the Walnut Creek police.



Thompson officially retired from being a police officer Monday, authorities said.



Thompson could be sentenced by a judge to a year in county jail. He will be back in court Oct. 10.

