Alhambra, California (CNN) -- At first, the pool builder thought his Bobcat bulldozer struck garbage as he dug a hole in a residential backyard. After all, in the older neighborhoods of San Marino, California, people used to bury their garbage.





But the plastic bag didn't contain trash.





Jose Perez, operating the Bobcat with his father as a co-worker, asked his dad what was inside. His father grabbed an 18-inch piece of reinforcement bar to poke around.





"He looked inside it, and he mouthed to me that there were bones in it," Perez testified Wednesday in a Los Angeles County court. "He thought it was a dog, but it didn't look like a dog.





"I told him to drop it, and he did," Perez continued. "It was a human skull."





As the prosecution witness referred to the plastic bag and the pool digging project in a photograph on a big screen in court, defendant Christian Karl Gerhartsreiter, in a blue jail jumpsuit, stared intently at the scene where prosecutors accuse him of murdering a man in 1985.





The skull was found nine years later, on May 5, 1994, Perez testified.





The testimony was evidence that Los Angeles County prosecutors began presenting during a preliminary hearing for the German-born Gerhartsreiter, who has garnered renown for impersonating a Rockefeller and inspiring a movie about the caper. He is now accused of killing a Southern California man who has been missing since the mid-1980s.





Frank Sheridan, a forensic pathologist, testified the skull suffered at least one blow to the forehead and at least two blows to the right side. The several fractures were made at or about the time of death, said Sheridan, who is also the medical examiner of San Bernardino County in California.





The shape of two fractures also indicated an object with a curved surface, such as a baseball bat, was used to deliver the blows, Sheridan said under questioning by a prosecutor.





"This individual was alive when these fractures occurred," said Sheridan, who examined a reconstructed version of the skull. In his career, he has performed 8,000 autopsies, he said.





"There's a lot of force involved in these blows," Sheridan added. "Each one of them would have rendered the person unconscious.





"The injuries we're talking about here would have very clearly been fatal in the absence of medical care, and they could have been fatal even with medical care," he said.





At the pool construction site, investigators eventually found nearly the entire skeleton of a man whose height was between 5 feet 4 inches and 5 feet 7 1/2 inches, testified Judith Daye, a physical anthropologist who worked for the Los Angeles County's coroner office and reviewed the bones at the site.





The missing bones included a kneecap, four fingers and a few toes, a common occurrence with buried remains, "especially the hands and feet because the bones are very small," Daye testified.





Many discovered bones were inside clothing that was wrapped in plastic, such as the pelvis inside jeans and the upper torso bones inside a shirt, Daye testified.





The preliminary hearing, to determine whether Gerhartsreiter should be bound over for trial, is expected to last six days, said Sandi Gibbons, a spokeswoman for the Los Angeles County District Attorney's Office.





Gerhartsreiter, 50, is accused of killing John Sohus, who was 27 at the time of his 1985 disappearance. His mother once owned the San Marino home where the remains were found.





During the Wednesday hearing, Los Angeles County Judge Jared Moses rejected a defense request that Gerhartsreiter be referred to as "Mr. Rockefeller" in court. The defense attorney said he and other attorneys on the team knew Gerhartsreiter as "Mr. Rockefeller."





But the judge said: "I get individuals in court who have a number of akas," a police term meaning "also known as," but "I have never seen a circumstance in court where a person is referred to by one of his akas."





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What was found fractured? at least how many blows did the skull receive Who is accused of murder? who was accused of murder what was found after the skull's discovery who did he clam to be What is Christian Karl Gerhartsreiter accused of Who did he once claim to be?
human skull." two Christian Karl Gerhartsreiter, Christian Karl Gerhartsreiter, nearly the entire skeleton of a man impersonating a Rockefeller of killing a Southern California man who has been missing since the mid-1980s. Rockefeller
question: What was found fractured?, answer: human skull." | question: at least how many blows did the skull receive, answer: two | question: Who is accused of murder?, answer: Christian Karl Gerhartsreiter, | question: who was accused of murder, answer: Christian Karl Gerhartsreiter, | question: what was found after the skull's discovery, answer: nearly the entire skeleton of a man | question: who did he clam to be, answer: impersonating a Rockefeller | question: What is Christian Karl Gerhartsreiter accused of, answer: of killing a Southern California man who has been missing since the mid-1980s. | question: Who did he once claim to be?, answer: Rockefeller