Boise man was charged with rape. He’s now accused of sexually assaulting a 15-year-old.

Roughly a month after prosecutors charged a 20-year-old man with rape, they’ve now filed another felony against him over an allegation that he sexually assaulted a teenage girl in 2022.

The Ada County Prosecutor’s Office charged Isaiah Williams, of Boise, with felony lewd conduct with a child under 16 after they said he raped a 15-year-old girl at a house party in October 2022. He was already facing two other felonies stemming from the November incident.

Ada County Deputy Prosecutor Austin Payne alleged in court last week that after meeting the girl at the party, Williams got her alone despite one of the girl’s friends trying to stop him and sexually assaulted her. He also knew she was underage, Payne added.

“There’s a serious danger to the community here as the defendant in this case committed an act of sexual deviance against a minor child — which poses a serious threat to the safety of children in Ada County,” Payne said.

Boise Police Department spokesperson Haley Williams told the Idaho Statesman by email that Williams was arrested on the most recent charge after another victim came forward. Detectives are still recovering information that indicates there are likely more victims, she added.

Any additional victims are encouraged to reach out to Boise Police Detective John Berg at 208-577-4448 or the Ada County Dispatch at 208-377-6790.

In November, the Boise Police Department arrested Williams for rape and forcible penetration by the use of a foreign object after he allegedly sexually assaulted a woman in his apartment. Payne said during a court hearing last week that Williams initially denied raping the woman but later admitted to police that the woman told him no.

“However, he would again force his hand down the victim’s pants, move her underwear to the side, and try to penetrate her vagina,” he added.

Williams previously worked for the Washington Department of Corrections but left the agency in August, according to a spokesperson.

As of Tuesday, Williams was being held at Ada County Jail. He bailed out of custody on a $20,000 bond in November and had been living with his brother in Olympia, Washington, according to court records. He was arrested again after he missed a hearing and the newest charge was filed.

“The defendant has demonstrated that he is a serious sexual offender, and anything besides significant bond will place Ada County citizens at risk of harm,” Payne said.

Fourth District Magistrate Judge David Manweiler set Williams’ bond at $500,000 for each case — totaling $1 million. His next court hearing is at 1:30 p.m. on Jan. 7 at the Ada County Courthouse, online court records showed.