Stunning Montana De Oro Beach and The Resident Stalker

Montana De Oro Beach is positioned adjacent to the community of Los Osos next to Morro Bay. The tides and current are a surfer’s paradise featuring ferociously breaking waves and miles of pristine sand dunes often isolated from extensive visitation. Montana De Oro is a picturesque summit to view a reclining sunset, but equally a remote and sinister location conducive to crime.

During the autumn of 1985, Mary Waterbury lived in San Luis Obispo with her sister. She was a liberal studies major at Cal Poly University, but had taken the fall quarter off to work as a bookkeeper. On October 19th, she drove to Montana De Oro in her sister’s yellow Volkswagen Bug but didn’t return home. The shy and slight Waterbury would be discovered suffocated half-clothed in the loose earth of the park after being raped. Authorities had a potential suspect in Arroyo Grande landscaper and sex offender Peter Derks, but lacked the evidence necessary to bring him to trial. Derks had previously spent time in prison for rape imprisoned for 11 years.

Two years following Waterbury’s murder, Derks stalked Julie Richter at Montana De Oro nearing sunset. He approached Richter with a club and threatened to beat her if she didn’t cooperate with his wishes. She had the presence of mind to throw her jar of collected shells in his face and run. She tripped falling to her hands and knees as he pursued. His face was covered in blood and as he was nearly on top of her, she threw a fistful of sand into his face. This time she escaped running to safety.

Derks would be apprehended for the attempted attack and plead guilty to the charge of assault with a deadly weapon. He was sentenced to nine years in state prison. Quoted in court, he stated that he had difficulty forming relationships with women.

In 2004, two San Luis Obispo County sheriffs were assigned to a series of unsolved cold cases including Mary Waterbury’s murder. Forensics technology had evolved significantly over twenty years and Derk’s DNA matched with the evidence accumulated in Waterbury’s killing. He was arrested for the murder upon the confirmation of the match.

In July 2005 at his trial, his attorneys attempted to convince the Superior Court judge the need for a special hearing on the scientific validity of the process. The judge turned down the request. The prosecution was prepared to conduct a trial seeking the death penalty. Derks pleaded guilty to the charges against him and was sentenced to life in prison without the possibility of parole.