ESCONDIDO, Calif. » A former driver for Uber and Lyft was charged today with sexually assaulting several women while on the job, and Southern California investigators said that there are likely more victims.

An 18-year-old college student reported that she was assaulted Friday afternoon after requesting an Uber car in a city near San Diego, said Escondido police Lt. Justin Murphy.

The woman told police that the driver picked her up on the Palomar College campus in San Marcos and immediately turned off the Uber app. She texted friends, telling them she felt uncomfortable, and then he drove her to another location where he attacked her inside his blue 2014 Chrysler mini-van, Murphy said.

Later that day, police arrested Jeremy Vague, 37, at his home.

The former college basketball player, who is 7 feet tall and weighs 270 pounds, pleaded not guilty today to multiple sexual assault charges. A phone listing for Vague could not be found and his attorney could not be reached for comment.

In the course of the investigation, Murphy said detectives discovered the additional victims, including two 19-year-old women in the neighboring city of Escondido.

Vague had given one of them a Lyft ride on Sept. 7, and the other was waiting at the destination. Vague asked to take a picture with the two of them and as they posed he touched them inappropriately, Murphy said.

On Sept. 6, another student, who had not requested a ride, called Palomar College police to report an Uber driver identified as Vague had tried to lure her into his minivan, but she had refused. Murphy said campus police contacted Vague and told him to stay away from the college.

It was unclear when Uber and Lyft were contacted about the assaults or when the companies ended his employment.

According to court records, Vague pleaded guilty to a misdemeanor charge of vehicle burglary in northern Utah stemming from a July 2002 incident. The Associated Press reported at the time that Vague and another man were arrested for stealing golf clubs.

No one at either company responded to emails asking whether they knew about his record and whether that would have prevented him from being hired.

In April, Uber agreed to pay at least $10 million to settle allegations by California prosecutors that it misled passengers about the quality of its driver background checks. San Francisco and Los Angeles prosecutors sued in 2014, saying Uber’s background checks were inferior to what taxi drivers undergo because they did not include fingerprint checks for past convictions. Instead, the San Francisco-based company’s process relies on a name search of other criminal databases and motor vehicle department files going back seven years.

Lyft settled a similar case last year by agreeing to pay $250,000 and stop claiming its background checks were among the industry’s best.

Both ridesharing companies are cooperating with authorities.

Lyft said in a statement that the company has “a strict zero-tolerance policy for any type of violent behavior, abuse or harassment and have permanently deactivated the driver’s access to the platform. Drivers on the Lyft platform undergo a thorough criminal background check across local, state and federal databases that go back in time to the maximum extent allowable by law.”

A statement from Uber said, “There is no excuse for the violent acts described and reported to police. We are working with law enforcement officials to fully support their investigation, and the driver has been banned from accessing the Uber app.”

Vague, who is married, had worked for Lyft for nine months and Uber for three months, Murphy said.

Vague also has worked as a coach for a high school girls’ basketball team in San Diego County. He played basketball for at least one season for Utah State University in 2000 and 2001, according to the team’s website.

A bill requiring stricter background checks for ride-hailing companies has passed the California Legislature and is awaiting Gov. Jerry Brown’s signature.

It would prohibit the companies from hiring drivers who are registered sex offenders, have been convicted of violent felonies or have a driving under the influence conviction in the past seven years.

Neither drugs nor alcohol were factors in the sexual assault cases, police said.

Police believe there may be more victims and Murphy urged them to call authorities.

“We’re asking you to find the courage to come forward so we can hold Vague accountable for his actions,” he said.