He was the last unfortunate victim of Brian Moser aka The Ice Truck Killer. He lost his life so that Brian could have "a set of wheels."
While Brian was taking Debra Morgan to the Moser Family House, he met with a man and hit him over the head with some sort of object that left him dead. He was then thrown into the trunk of his car along with Debra, who continued to scream as the tape around her mouth came loose. Brian stopped the car, stepped out, and quoted the following:
"Sorry, but you're drowning out Fred's radio and he was kind enough to lend us his wheels."
Fred was never mentioned again. It is unknown if his body was found inside his vehicle at the Moser household.