Gerhartsreiter -- who was convicted in April of murdering his landlady's son, John Sohus -- maintained his innocence as he was sentenced Thursday, the Los Angeles Times reported.
Sohus was 27 when he was bludgeoned to death in 1985 and placed in a shallow grave behind a guest house at his San Marino, Calif., home, where Gerhartsreiter had been living.
Sohus' wife, Linda, also vanished and was never found.
"I want to assert my innocence and that I firmly believe that the victim's wife killed the victim, but be that as it may, once again, I did not commit the crime," Gerhartsreiter, 52, said in court Thursday.
Gerhartsreiter has passed himself off as a British aristocrat, a film and television producer, a bond trader and as Clark Rockefeller -- a pose he used successfully to develop an upscale lifestyle in Massachusetts.
During closing arguments at his trial, Los Angeles County Deputy District Attorney Habib Balian told jurors Gerhartsreiter "thinks he's smarter than everyone."
The largely circumstantial case against Gerhartsreiter had its big break when he gave the victims' truck -- which he had taken when he left San Marino -- to a friend. Gerhartsreiter came to investigators' attention when the friend searched for the vehicle's title.
The defense argued Gerhartsreiter was a con artist but not a killer.
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