At least nine Miami police officers are expected to face federal criminal charges or internal discipline from a broadening FBI investigation into a suspected protection scheme involving a Liberty City gambling ring and other criminal activity, The Miami Herald has learned.

Six of those officers have already resigned or been relieved of duty in recent weeks in connection with the investigation, according to sources close to the probe. The FBI, working with Miami police internal affairs investigators, is expected to make arrests before the end of the month.

The officers, who worked in the Model City substation, are suspected of providing off-the-books protection to a Liberty City barber shop that served as a front for an illegal sports-betting operation busted last March. Officers frequented the barber shop so often that one gambler told county police he thought the place was being run by the Miami Police Department, court records show.

This week, two officers were relieved of duty, according to the department. They were Nathaniel Dauphin, 41, who helped organize the unauthorized protection detail, and Malinsky Bazile, 27, who is suspected of other criminal activity. Both will continue to receive pay while the investigation continues.

Last month, The Herald reported that 31-year-old officer Lashunda Hodge was relieved of duty with pay as part of the probe.

Another likely target of the investigation, officer Harold James, resigned Nov. 27. In his resignation letter, James gave no reason for leaving, but in a notice submitted to the Florida Department of Law Enforcement, police administrators said James resigned because he was under investigation for a crime involving “perjury or a false statement,” records show.

At least three other Miami officers are facing scrutiny in connection with the protection scheme: Hodge’s roommate, Kenya Crocker, 39; Dauphin’s girlfriend, Carol Vargas, 39; and Darryl Bryant, 51, according to sources familiar with the case.

The sources said another officer, Vital Frederick, 26, was recently relieved of duty, but a department spokesman said Wednesday that he remains on the job. A message left at Frederick’s home was not returned.

The FBI investigation has focused largely on Hodge and Dauphin. Investigators believe Hodge was the original ringleader of the protection scheme, and Dauphin later managed the operation, sources said. Hodge’s lawyer has denied that she set up the protection; Dauphin could not be reached for comment.

Sources say the officers received thousands of dollars in unsanctioned payments to provide off-duty protection to the Player’s Choice Barber Shop, 6301 NW Sixth Ave., from mid-2010 through last March.

On March 26, Miami-Dade police detectives raided the barber shop and two other South Miami-Dade locations following a six-month gambling investigation dubbed “Operation Pass the Buck.” Five men were arrested on gambling charges, accused of organizing bets on football and basketball games in the back rooms, court records show.

The off-duty police work at Player’s Choice, which has since closed, was not approved through proper channels, the sources say.

In response to a public records request, the police department provided five “special events” forms listing officers working off-duty at Player’s Choice from October 2010 to April 2011. Two of those forms were prepared by Dauphin, who is listed as the off-duty officer working at the shop on 36 nights, the records show.