The man was a fire captain stationed in the scandal-plagued city of Bell, and authorities said he appeared to be at least partly operating his piece of the Costa Rica-based online sportsbook on duty.
On Monday, now-retired Los Angeles County Fire Capt. Tod Hipsher pleaded guilty in Santa Ana to a federal charge of running an illegal gambling business. Hipsher, 51, who remains free, is set to be sentenced on June 2 and could face a maximum of five years in prison.
"We have great respect for firefighters and first responders," said Josh Robbins, an assistant U.S. attorney prosecuting the case. "It's disappointing when someone in an official position, especially someone in a position of leadership and responsibility, chooses to be involved in illegal activity of any kind."
Los Angeles County fire officials had no immediate comment on the case. Hipsher declined to comment after the hearing.
The ongoing federal investigation into Hipsher and at least a half dozen associates began in 2009 following a tip from the Orange County District Attorney's office. Another Orange County man, Pat Fondarella, has pleaded guilty to running an illegal gambling business on another website and is scheduled to be sentenced later this year.
Authorities say Hipsher netted hundreds of thousands of dollars over 12 years by recruiting bettors and collecting debts for the online Tradewinds sportsbook—which took wagers on the Super Bowl, college basketball games and other events.
He set up clients with accounts so they could bet online or through a 1-800 number.
There are hundreds of offshore sportsbooks operating online but it is illegal to use them from the United States, homeland security officials said. Tradewinds is based in Costa Rica, where sportsbooks are allowed, and has not been charged in this case, officials said.
In 2011, undercover agents met at least twice with Hipsher at the fire station in Bell, said Mark Speidel, a special agent with Immigration and Customs Enforcement's homeland security investigations.
"It appeared he was operating a portion of the gambling business while on duty," Speidel said.
In March, authorities said they searched Hipsher's Irvine home and seized $200,000 in cash. Hipsher retired from his fire department job at the end of 2013.
Hipsher told authorities he made between $200,000 and $300,000 from the sportsbook over the past few years, Speidel said, adding that some bettors interviewed by investigators said they had been financially ruined. One gambler lost just under $1 million, Speidel said.
Hipsher and federal authorities reached a plea agreement in October but he did not plead guilty in court until Monday.
Hipsher's lawyer, Victor Sherman, told the court the delay allowed his client to retire at the end of last year.
In recent years, the Los Angeles suburb of Bell has been recovering from a separate, political corruption scandal after top administrators and elected officials were charged with, and later convicted of crimes including conspiracy and misappropriating public funds.