An Uber driver in San Francisco was arrested Friday for attacking a taxi passenger with a hammer, according to police. The rider was so badly injured that he may lose an eye because of the attack.

The victim, Roberto Chicas, and two friends scheduled an Uber ride Tuesday and, on getting in, began disputing with the driver over which route they were taking to their destination, as reported by the Bay Area ABC affiliates. After yelling at the passengers to get out of the car, police said the driver began attacking them.

When police arrived, the driver had already left and Chicas was slipping in and out of consciousness

Chicas is still recovering from serious head fractures and other injuries. The driver was later arrested in his home in Pacifica.

San Francisco District Attorney George Gascon said that the 26-year-old driver Patrick Karajua pleaded not guilty to the hammer attack. He was charged with assault with a deadly weapon and battery with serious bodily injury in San Francisco Superior Court. He is free on $125,000 bail.

Just days before the incident, Gascon and the Los Angeles County District Attorney Jackie Lacey told services like Uber, Lyft and Sidecar that they could face civil penalties for illegal operations. The lawyers say that the ride sharing businesses mislead clients by claiming they screen drivers with background checks to weed out people with criminal offenses and driving violations.

Uber released a statement following the hammer attack incident.

"Safety is Uber's No. 1 priority. We take reports like this seriously and are treating the matter with the utmost urgency and care," Uber spokeswoman Eva Behrend said. "It is also our policy to immediately, suspend a driver's account following any serious allegations, which we have done. We stand ready to assist authorities in any investigation."