(CNN) -- One of the largest Jewish cemeteries in the Los Angeles, California, area has been accused of desecrating the remains of those buried there, according to a lawsuit.
The cemetery holds the remains of celebrities such as Groucho Marx and Lenny Bruce.
The suit, filed Thursday in Los Angeles Superior Court, alleges that employees at Eden Memorial Park, in Mission Hills, California, "intentionally, willfully and secretly desecrated the remains of deceased individuals," often moving them to make room for new remains.
Attorney Michael Avenatti, who filed the suit, told CNN that his investigation revealed that as many as 500 graves may have been torn up without the families' permission.
"We allege that Eden Memorial Park and its management for the better part of 15 years were engaging in improper burial practices, including the desecration of graves and the improper disposal of human remains," he said.
The lawsuit is filed by F. Charles Sands, whose parents are buried at Eden Memorial Park, against the cemetery and its owner, Service Corporation International, based in Houston, Texas. The company is the largest owner of cemeteries and funeral homes in the United States. Watch what the lawsuit says workers did to remains »
This is not the first time Service Corporation International has faced allegations of digging up graves and moving bodies to make room for new remains. It reached a $100 million settlement with families of people whose remains were desecrated at Menorah Gardens in Florida. The company also reached a $14 million settlement with the Florida state attorney's office over issues related to those claims.
A number of celebrities are buried at Eden Park, including comedians Groucho Marx and Lenny Bruce, according to several Web sites that track burials of celebrities.
Anthony Lampe, the general manager of Eden Memorial Park, said he had not seen the lawsuit and referred inquiries to Service Corporation International. Company spokeswoman Lisa Marshall said the allegations in the lawsuit were not valid. She said SCI had investigated and confirmed burial issues at Eden Memorial Park in 2007, but she could not provide specifics of that investigation.
The lawsuit alleges groundskeepers were secretly instructed to break buried concrete interment vaults that contained caskets that were already buried, using backhoes. It also alleges human remains would often fall out of the broken caskets, and those body parts were either scattered or thrown away.
In one case, Avenatti said, a human skull was discarded.
"We have uncovered evidence that the groundskeepers and others at Eden Memorial Park have been instructed to break off or break apart that concrete vault and, at many times, that exposes human remains," Avenatti said.
Asked about the seriousness of the allegations, he said, "If the allegations are proven true, this is incredibly horrific."
The lawsuit said that under Jewish tradition, "the deceased are typically required to be interred within 24 hours, thereby leaving little time to obtain consent to move an encroaching vault in an adjacent plot and giving defendants a motive to desecrate human remains and commit other immoral acts rather than comply with the law."