CANCUN, Mexico - The producer of "Pimp My Ride" and formerly of "Survivor" was released from Mexican custody early Friday, but remains under investigation after his wife's body was found in the sewer of a swanky Cancun resort, a state official said.

Bruce Beresford-Redman must remain in Mexico after being released just past midnight Friday, Quintana Roo state investigator Veronica Acacio said.

"He won't be able to leave the country until we conclude our investigation into what caused her death," Acacio said.

Police detained the 38-year-old producer as a suspect Thursday after finding the body of Monica Beresford-Redman in a sewer at Cancun's Moon Palace resort, where the family was on vacation.

Her body had scratches on the neck, signs of asphyxiation and a heavy blow to the right temple, said Francisco Alor, the attorney general for Quintana Roo state, where Cancun is located.

"What we need to determine is whether that blow was from falling into the sewer," Alor said late Thursday, adding that authorities had determined she died Monday night.

Her husband had scratches on his face and arms, he said, and several guests heard an argument in the couple's room Monday night. Bruce Beresford-Redman told a hotel employee sent to check that they were fighting over their two children, according to Alor.

"He's the initial focus of the investigation based on their alleged turbulent relationship," Alor said by phone from the state capital of Chetumal.

The television show producer told police on Tuesday that his wife had left the hotel to go shopping the previous day and never returned. A lawyer for Bruce Beresford-Redman could not be located.

Earlier Thursday, then-state Attorney General Bello Rodriguez said a security guard at the hotel saw the couple arguing Monday night and Beresford-Redman tried to hit her. Coincidentally, Thursday was the day Rodriguez stepped down as Quintana Roo's attorney general and was replaced by Alor.

In Los Angeles, friends gathered at the Zabumba bikini bar and restaurant that Monica Beresford-Redman owned and managed, saying they hoped her death was an accident and not murder.

"She's going to be very missed," said friend Mariza Alyrio. "I can't believe it's her. I hope he didn't do that. I don't want to believe it. He doesn't seem like that kind of guy."

Monica Beresford-Redman would have turned 42 on Thursday.

Brazilian media reported that she was born in Rio de Janeiro and her parents still live in the South American country.

"They weren't lovey-dovey, at least when I saw them, and they didn't smile a lot," said Ratana Necth, 36, a nanny for a family in the Palos Verdes, California, neighbourhood where the Beresford-Redmans and their two children lived. Necth described the couple as nice and said they always seemed "on the go."

Bruce Beresford-Redman was a producer for several episodes of the Emmy-nominated CBS reality show "Survivor," including "The Amazon" and "Marquesas" seasons, but was not currently working with the program, according to his profile on IMDb.com.

The Internet Movie Database also names him as the co-creator of "Pimp My Ride," a popular MTV car makeover show, and as an executive producer for "Crash Course," a driving game show produced by A. Smith & Co. Productions that aired on ABC last summer.

Beresford-Redman was nominated for three Emmys for his work on "Survivor," the long-running reality TV competition that strands tribes of strangers in remote locales to outwit, outplay and outlast each other for a $1 million prize.

Bruce Beresford-Redman worked for reality TV giant Mark Burnett, who produces "Survivor" and is currently producing Sarah Palin's eight-part series about her home state of Alaska.