Marquez met Clark two years before the murder, and the two became friends.
Marquez had even lived with Clark at times when he had no permanent place to stay.
But in July 2006, Clark caught Marquez attempting to steal fishing poles from the home and kicked him out.
A month later, on August 5, 2006, Marquez returned to the San Clemente home with the intention to burglarize it.
When confronted by the victim, Marquez used two knives to stab Clark 98, one of which broke by the force of the stabbing.
Marquez also killed Clark's poodle-mix "Charlie," stabbing him 60 times.
The suspect then ransacked the house and drove away in Clark's pickup truck.
He was later found sleeping on the side of the road and was arrested for DUI.
Clark's stepfather noticed the truck was gone, and when Clark didn't return, he entered the home and found the body on the bathroom floor.
The man called police, who linked the missing truck to Marquez.
DNA evidence also matched the Marquez to the victim and the crime scene.
During the trial Marquez said he went to the home to apologize for the fishing poles, blacked out, and didn't remember committing the murder.
He faces a maximum of life in prison without the possibility of parole when he's sentenced on April 24.
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