The U.S. Attorney’s office in Los Angeles announced Friday that three more conspirators pleaded guilty in the insurance fraud case tied to Pacific Hospital of Long Beach – now College Medical Center.

Michael R. Drobot, the son of the medical consortium’s former Chief Executive Michael D. Drobot who pleaded guilty in 2014 – headlined the new slate guilty pleas. He admitted to inducing doctors to participate in a scheme to defraud insurers using false workers compensation claims. The junior Drobot was joined by Michael Barri, a San Clemente chiropractor, and Linda Martin, a Clovis-based marketer for the Pacific Hospital group. The three guilty pleas put the total number of criminal defendants tied to the case at nine.

Lawyers for Drobot, Barri and Martin did not immediately respond to request for comment.

A related civil racketeering case filed on behalf of the California State Compensation Insurance Fund, which seeks to recoup $160 million in alleged fraud-tainted payments, is ongoing in Santa Ana federal court.

The charges stem from a widespread scheme masterminded by the elder Drobot in which spinal surgery patients were referred to Pacific Hospital by doctors around the Southland in exchange for kickbacks. The hospital then billed insurers for more than $580 million related to these patient referrals, many of which were bogus or included inflated medical costs.

The scheme came crumbling down in 2013 when the FBI raided Drobot’s offices in Newport Beach. Pacific Hospital, which was at the center of the scandal, was quietly bought by College Health Enterprises Inc., a Santa Fe Springs-based healthcare management company, in 2014 for an undisclosed amount. It was rebranded as College Medical Center shortly thereafter.