The woman said the attack happened in a dimly lit part of the jail.
The officer ordered her to take off her clothes, then groped her breasts, the woman said. She claimed the lawman forced her into sexual acts again and again, threatening to remove her from educational classes if she did not comply.
The former inmate, who made the accusations in a lawsuit filed Friday, also claims Sheriff Jim McDonnell and other county officials had been notified of Scotti's behavior and put the deputy on probation but allowed him to maintain contact with inmates. It was during this time, in August of last year, that the woman claims she was assaulted.
The woman could be one of the six victims included in the criminal case against the deputy, said one of the woman's lawyers, Araksya Boyadzhyan. The attorney said her client was interviewed by internal department investigators about the incidents but has not received a subpoena.
A lawyer representing Scotti in the criminal case, Anthony Falangetti, did not immediately respond to requests for comment Friday evening.
The 41-year-old inmate was six months into serving a DUI sentence at the Century Regional Detention Facility in Lynwood when Scotti approached her in a recreational space where there was minimal lighting, according to her lawsuit.
The deputy demanded that she reveal her breasts, she said. When she tried to resist, he told her, "You do what I say, or else it is going to be really bad for you here," the lawsuit says.
In another incident, Scotti, 31, placed the woman's hand on his penis, and on other occasions, he forcibly kissed her, according to her complaint.
The woman was captured on surveillance video during at least one of the assaults, Boyadzhyan said. The lawyer said officials would have been aware of the act by looking at the footage but did not remove Scotti for at least several days.
The Times generally does not identify people who report being victims of sexual assault.
"Deputy Scotti is still relieved of duty without pay," department spokeswoman Nicole Nishida said late Friday. "We are aware of the civil claim and have been investigating the allegations."
A report issued by independent auditors found that the Century facility is lagging behind on implementing federal requirements designed to prevent sexual assault and harassment in jails and prisons.
The findings, made public in March, said the lockup was out of compliance on nearly every standard set by the federal Prison Rape Elimination Act of 2003. Auditors noted that some inmates could be seen while showering and that complaints could be intercepted by officers who might be the targets of allegations.
The Sheriff's Department, which runs the jail, has said it has made some improvements, including educating inmates about their rights and on how to file complaints.