John Tlumacki/The Boston Globe via Getty Images

For more than 25 years he had five identities, becoming a world class con artist across high class society.

He was a physicist, an art collector, a ship captain and a financial advisor. The German immigrant even went by Clark Rockefeller, claiming to be an heir to the Rockefeller fortune.

Christian Gerhartsreiter, his true identity, showed up today in California for his preliminary hearing as a thin white male with glasses handcuffed in a blue jumpsuit. He is accused of murdering the son of his former landlady, John Sohus, in the mid 1980's.

Lawyers today asked Superior Court Judge Jared Moses if Gerhartsreiter could be called Clark Rockefeller throughout the trial. The judge responded a bit shocked, ruling Gerhartsreiter must be called by his real name.

The hearing is expected to last around 6 to 8 days where prosecutors will try to convince Superior Court Judge Jared Moses there is enough evidence showing Gerhartsreiter is responsible for the death of Sohus.

In the early 1980's, Gerhartsreiter was living as one of his pseudonyms: Christopher Chichester.

Posing as English royalty and claiming to be involved in the film industry, Gerhartsreiter settled down in a guest house the small wealthy town of San Marino, Calif.

During the time of Gerhartsreiter's stay in 1985, the landlady's son and daughter, John and Linda Sohus, vanished. Gerhartsreiter was also nowhere to be found.

Not until 1994 would police come across a lead in Sohus' disappearance.

A new home owner in San Marino had discovered skeletal remains in the backyard of the house while building a pool.

Authorities confirmed for the first time last year that the skeletal bones were that of John Sohus. The premature technology of DNA testing during that time and the fact Sohus was an adopted child delayed the definitive identity of the bones.

"Modern technology has helped us to identify those bones as the Sohus bones," Los Angeles County Sheriff's spokesman Steve Whitmore told The Associated Press.

That modern technology has brought prosecutors their key witnesses in the preliminary hearing today, including Sohus's sister who provided the DNA to identify the bones.

Sohus's sister, Lori Moltz, testified she had given police a DNA cheek swab that confirmed the skeletal remains were that of Sohus. While Moltz admitted she had no idea she had a brother, she was able to verify her mother's handwriting on his birth certificate.

Prosecutors then called their second witness Jose Perez, the worker who discovered the bag of bones in May of 1994 while digging to build a pool in the backyard.

"When I dug into the ground, I thought I hit a box," Perez testified. "When he (his father) looked inside it, he discovered some bones."

Perez soon realized it was human remains. He then called the police, left the backyard and waived down  Officer Kelvin Wang of the San Marino police department. Wang testified today he was the first to arrive on the scene and that he secured the area before handing it off to detectives.

When showed the remains in court today,  Gerhartsreiter's face was emotionless.

On the other hand, the defense suggested the 26-year-old cold case has jogged some of the witness's memories. Defense went after Officer Wang's lack of memory during the day the bones were discovered.

But prosecutors say Gerhartsreiter eluded police for years by moving to Boston and New York. Gerhartsreiter made his way among the elite, marrying a woman with whom he had a daughter. The couple divorced when she found out his true identity.

Last year, Gerhartsreiter was convicted of kidnapping his daughter in Boston during a custody dispute. He is now serving a four to five year prison sentence, and would be eligible for parole this year if not awaiting trial on a murder charge.

If convicted in the murder of John Sohus, Gerhartsreiter could face 26 years to life in prison.