Alameda County District Attorney Nancy O’Malley is expected Friday to announce decisions about charges in a sexual misconduct scandal rattling several Bay Area law enforcement agencies.

The woman at the center of the case, a 19-year-old sex worker from Richmond who calls herself Celeste Guap, said she had sex with 29 officers from various cities over the past two years. Some of the encounters took place when she was a minor.

Among the officers Guap named was a Contra Costa County sheriff’s deputy who she said would pick her up and drive to a secluded road near the Caldecott Tunnel. Guap said the two had sex in his car “about 10 times” when she was 17.

The deputy, Ricardo Perez, resigned in June, shortly after The Chronicle published an account of his actions. He had been the subject of a disciplinary probe and a criminal investigation.

Oakland, meanwhile, has struggled with the fallout of the scandal, which prompted the abrupt resignation of Police Chief Sean Whent in June. Whent, who was known as a heavy hitter in internal affairs, was well liked in City Hall and touted as a reformer. Within a week, two subsequent bosses left the department, which is currently led by City Administrator Sabrina Landreth.

Guap, who is the daughter of an Oakland police dispatcher, is participating in a rehabilitation program in Florida.

Four Oakland police officers face termination after a separate investigation by city officials, which found that each officer had committed at least one of several offenses, including attempted sexual assault, shielding prostitutes from arrest, and lewd conduct in public.

Seven officers face suspension without pay for other offenses, such as failing to report allegations that their peers had sex with a minor and using law enforcement databases for personal gain. One officer was referred to counseling.

More for you News Livermore officer quits, sex misconduct scandal fallout...

Livermore police announced Thursday that one of their officers resigned after supervisors became aware of his sexual relationship with Guap. He was placed on administrative leave and quit on Sept. 2, after an internal review of the accusations.

Rachel Swan s a San Francisco Chronicle staff writer. Email: rswan@sfchronicle.com Twitter: @rachelswan