Christian Gerhartsreiter is accused of killing John Sohus in San Marino, a wealthy Los Angeles suburb, in 1985. Sohus was the son of a woman who rented her guest house to the defendant.
Nearly 30 years later, Gerhartsreiter was identified as the prime suspect for Sohus' murder.
The suspect attentively sat in court Monday, scribbling down notes as the prosecution told the jury how they would prove Gerhartsreiter killed his landlady's son.
The victim, a 27-year-old computer programmer, vanished along with his life Linda in 1985. Bones believed to be that of Sohus were found buried in the yard of the San Marino home in 1994. The victim's wife remains missing but is presumed to be dead.
According to authorities, Gerhartsreiter has assumed various aliases over the years.
The prosecutors outlined the suspect's lies Monday claiming he was an impostor to so many who believed what he told them. The German immigrant identified himself as Chris Chichester while he lived in the San Marino guest house.
"The people of San Marino believed him. He convinced them," Deputy District Attorney Habib Balian said. "You will learn that he didn't just use his words to convince people. He used objects, he used documents to put forth his lies."
However, Attorney Brad Bailey, disclosing his defense for the first time, suggested that the missing wife could be the real killer.
The defense said Linda Sohus mailed her friends and family postcards from Europe after going missing.
But prosecutors said she didn't have a passport, and that Gerhartsreiter arranged for the postcards to be mailed as part of a ruse.
Bailey said there are no witnesses to the killing or burial of Sohus and prosecutors have little more evidence than the bizarre behavior and multiple identities of Gerhartsreiter to paint him as a murderer.
When Chichester suddenly vanished from San Marino, residents didn't connect him with the disappearance of the Sohuses.
For two decades, the suspect also allegedly fooled people by posing as Clark Rockefeller for 20 years, a member of the wealthy family.
According to authorities, Gerhartsreiter used the connection to worm his way into high society, talk his way into important jobs and marry a wealthy woman.
The suspect's identity was unraveled when he kidnapped his then 7-year-old daughter in Massachusetts during a custody dispute. The suspect was serving time for the kidnapping when authorities learned of his numerous identities and charged him with Sohus' murder, which interrupted his chance to regain freedom.
Gerhartsreiter has pleaded not guilty to the murder charge.
The Associated Press has contributed to this report.