Los Angeles, California (CNN) -- Reality TV producer Bruce Beresford-Redman, accused of killing his wife at a Cancun resort in April, could remain free for months while a Mexican federal judge re-examines the evidence in his case, his lawyer in Mexico said.
Beresford-Redman was charged with murder in May and Mexico delivered an extradition request to the U.S. Embassy in June, but nothing has been sent to the U.S. Attorney in Los Angeles where he lives, according to a spokesman there.
His late wife's sisters have asked Secretary of State Hillary Clinton to help speed up the extradition, but so far they've been given no information about the process, their lawyer said.
Monica Beresford-Redman's body was found in a sewer at the Moon Palace Resort on April 8.
The initial investigation suggested she "died of strangulation, because of the bruising," Mexican regional police spokesman Adrian Cardena said.
The couple was at the resort with their two young children on a trip.
The former "Survivor" producer's lawyers filed an "amparo" with a federal court in Mexico City, a document arguing there is not probable cause to charge him. This triggered a review by a Mexican federal judge that could take nine months to complete, defense attorney Jaime Cancino Leon said.
"We are obviously concerned that the army of attorneys working on behalf of Bruce Beresford-Redmond, both here and in Mexico, would do anything possible to stall the extradition process," said Alison Triessl, a lawyer helping Monica Beresford-Redman's sisters.
The sisters "reached out to Secretary of State Hillary Clinton and asked if she would assist without delay in the carrying out of Mexico's request for extradition," Triessl said Friday.
The U.S. State Department and the Justice Department have not made public any information about when the extradition request might be executed.
Cancino Leon suggested the re-examination of the evidence by the federal court in Mexico might explain the delay.
"When we analyzed the case, we saw a lot of errors," Cancino Leon said. Forensic and medical experts hired by the defense identified problems with the autopsy, the gathering of evidence and the conclusions made by local investigators, he said.
The federal judge, who will decide if the murder warrant will stand, has not yet ruled if he will consider the defense expert evidence, Cancino Leon said.
If that judge upholds the murder warrant, Beresford-Redman's lawyer said it would be appealed to a higher court.
His Los Angeles lawyer, Richard Hirsch, has said he would challenge the extradition if it ever makes it to U.S. courts.
Hirsch accused the state judge in Mexico of "a rush to judgment" in charging Beresford-Redman, saying "it appears that this case is being handled in a manner outside the normal procedures in Mexico."
The producer was briefly detained after his wife's body was found in April. His passport was taken by investigators, and he was told not to leave Mexico until the inquiry was concluded. Beresford-Redman returned home in May, without the knowledge of investigators, to take care of family business and see his children, his lawyer said.
He still lives in his Rancho Palos Verdes home with his two young children, although his parents have temporary legal custody of the children, ages 3 and 5.
Bruce Beresford-Redman built his career as a Hollywood reality television show producer. He worked for several seasons on the popular CBS show "Survivor," in which contestants compete against each other in a variety of extreme outdoor scenarios. He was nominated for three Emmy Awards as a producer on the show and was last credited as a producer in 2004.
He also worked on NBC's "The Contender" and "The Restaurant," as well as MTV's "Pimp My Ride," according to entertainment media company IMG.
Monica Beresford-Redman, a native of Brazil, owned a restaurant in Los Angeles.