The six men and six women spent a half-day behind closed doors after the case was placed in their hands. They went home for the day without reaching a verdict.
John and Linda Sohus were reported missing 28 years ago this week. The newlyweds lived with John Sohus' mother in San Marino. In 1985, the couple simply vanished.
Nine years later, workers building a swimming pool found John Sohus' remains buried in his own back yard. Eventually, suspicion turned to Gerhartsreiter, the German immigrant who had been renting a guesthouse on the property.
On Tuesday, prosecutors made their final arguments in their case against Gerhartsreiter, who gained notoriety on the East Coast as a con man who posed as a member of the Rockefeller family. Gerhartsreiter's true identity was revealed after he was arrested for kidnapping his daughter in a midst of a custody dispute with his ex-wife. But prosecutors say his crimes in Boston pale in comparison to what he did in San Marino.
Gerhartsreiter defense attorney argued that prosecutors have never offered a motive for the killing and they said John Sohus was probably killed by his wife, Linda, who has never resurfaced.
Prosecutors said Linda was probably also murdered. Linda's best friend, Sue Coffman, thinks the same thing. Coffman said John and Linda Sohus were a loving couple with a bright future.
"I think she was killed shortly thereafter or maybe a few weeks later when he took her away," Coffman said. "Something went wrong and he's responsible, so in my mind that makes him a murderer."
There were no eyewitnesses to the crime and there was no physical evidence directly tying Gerhartsreiter to the murder. His defense hopes that will create enough reasonable doubt with the jury. Prosecutors hope the jury will see that there is enough circumstantial evidence that points to Gerhartsreiter as the murderer.
Jurors were to resume their talks on Wednesday.
The Associated Press contributed to this report.