A University of Michigan student told police that when she tried to leave an Uber ride early Friday morning upon reaching her destination, the driver reportedly “demanded money or a sex act,” according to the university’s police department.

Police are investigating the “suspicious incident,” which, the student said, began after she joined someone already in the vehicle. It was described as a dark-colored, four-door sedan.

“We are urgently gathering as much information as possible about this troubling report,” Uber spokeswoman Brooke Anderson said Friday. “We have contacted University police and will assist them in every way we can.”

It could not be independently verified that the car was operated by an Uber driver or booked through the Uber application.

Passengers riding in Uber vehicles pay via the Uber app, pre-loaded with credit card information, rather than handing over cash.

The allegation in Michigan came just days after police arrested an UberX driver in Denver for attempting to burglarize a passenger’s home. That driver’s access to the Uber database was “immediately deactivated,” the company said in a statement this week, adding: “We remain committed to supporting the Denver law enforcement in any way we can.” The company also said it performed a background check on the driver prior to hiring him, and he had no criminal record.

Other safety controversies have sprung up in recent months involving Uber drivers and accusations of sexual misconduct or assault, including a Chicago driver charged with sexually assaulting a passenger in December, and a Los Angeles-area driver being investigated for an alleged sexual assault in February.

According to Uber, the company conducts county, federal and multi-state background checks that extend seven years back on its drivers. It also screens the National Sex Offender Registry and looks at driving records.

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[This post has been updated.]