OAKLAND — The lead plaintiff in the infamous Riders case was charged Thursday with felony assault with intent to commit a sex crime, reportedly against a 17-year-old girl at an East Oakland motel, according to court documents.

Delphine Allen, 38, made headlines in the early 2000s when he was the first of 119 plaintiffs to sue the city for actions committed by the Riders, a band of rogue police officers who were accused of beating and planting drugs on West Oakland residents.

The civil case would become known as Allen v. City of Oakland. It ended in a $10.9 million payout to the plaintiffs and their attorneys, John Burris and Jim Chanin, and a 2003 negotiated settlement agreement requiring the Oakland Police Department to achieve reforms under federal oversight. The oversight continues to this day, 13 years later.

Oakland police Officer Alonzo Weatherly, in a court affidavit, said that 10 months ago Allen befriended a 16-year-old girl who considered him a “big brother or father figure she never had.” The pair would reportedly smoke marijuana together and Allen would help her out financially, giving her $20 here or there and $100 for her 17th birthday, according to court records.

On Tuesday, Allen took the teenager to a fast food restaurant off Hegenberger Road near the Oakland International Airport and gave her $200. They then drove to a motel in the 8400 block of Edes Avenue, where they smoked pot and Allen told the girl he wanted to have sex with her, Weatherly wrote. She refused.

Allen reportedly forced her to the floor of the motel room and sexually assaulted her, according to records. The girl was able to call her mother and run out of the room.

Allen was arrested Tuesday about 7:20 p.m. in the 8100 block of Bancroft Avenue. He appeared before a judge Thursday and is awaiting a court-appointed attorney. Allen returns to court Friday. The West Oakland resident has a prior 2004 conviction for selling drugs.

The Riders criminal case, the longest in Alameda County history, ended in dropped charges against three officers — Clarence “Chuck” Mabanag, Matt Hornung and Jude Siapno — after two juries failed to reach verdicts. A fourth officer and the alleged ringleader, Frank Vasquez, fled before the criminal trials and remains a fugitive. Authorities believe Vasquez may have left the country.

During the criminal trials Allen testified that the officers beat him with their batons and planted drugs on him. As of Thursday afternoon, the Alameda County Sheriff’s Office jail records listed Allen’s bail at $105,000.

Burris was surprised by the arrest and said Allen has “been a law-abiding person” since the Riders case and recently was working as a plumber.

“It’s hard for me to believe he would be involved in something like this. I’m sure there’s more to the story,” Burris said.

Staff writer Malaika Fraley contributed to this report.