Charges have been dropped against a woman accused of sexually assaulting a 16-year-old Japanese exchange student.

A trial against Rika Shimizu, 36, was supposed to start next week. But prosecutors dropped charges against her last week. They say in court documents the alleged victim has refused to testify.

A grand jury previously indicted her on five counts of second-degree sexual assault and four counts of fourth-degree sexual assault.

Authorities said Shimizu operated a boarding home for Japanese students who were attending school in Honolulu. Authorities alleged she assaulted a boarder while the boy was bedridden with an injury.

The boy told police that Shimizu assaulted him at least 10 times, according to court documents. The boy’s injury had left him incapacitated, unable to go to the bathroom alone, prepare meals or change clothes.

Shimizu had threatened to claim the boy had raped her if he reported the assaults, according to the court documents.

She denied the allegations.

A judge threw out key evidence against Shimizu after finding serious flaws with the police investigation, including not having a warrant to enter her home and failing to provide her with a Japanese interpreter, Hawaii News Now reported .

Prosecutors still have an opportunity to refile charges.

“She wanted her day in court and prove she was not guilty and that was taken away from us,” defense attorney Victor Bakke told KHON-TV. “Without that permanent dismissal, she has no closure to the case. She’s facing prosecution, immigration consequences, business consequences.”

Prosecutors offered to reduce felony charges to a misdemeanor but Shimizu refused, her attorneys said.

She spent 45 days in jail.