California prosecutors said an Uber driver living in the country illegally has been charged with raping, assaulting and robbing young women.

San Luis Obispo County District Attorney Dan Dow said Monday that Alfonso Alarcon-Nunez's alleged four victims are between 19 and 22 years old and three were intoxicated when they were assaulted.

The 39-year-old Mexican citizen faces 10 criminal charges including forcible rape and first degree burglary for the alleged incidents that occurred on December 17, 2017, January 5 and January 14.

Alfonso Alarcon-Nunez, 39, has been charged with sexually assaulting at least four women in California. The Uber driver allegedly targeted intoxicated women after parties, soliciting them for rides and then assaulting and robbing them once at their homes

Alarcon-Nunez is suspected of having sexually assaulted at least four women in California's San Luis Obispo, but authorities said there could be additional victims in the county and its neighboring Santa Barbara, KSBY reports.

Alarcon-Nunez, who has also used the name Bruno Diaz, was arrested at his Santa Maria, California home on January 17.

Authorities then discovered that he is an undocumented immigrant, who had returned to the US illegally after having been voluntarily deported from New Mexico in 2005.

He now faces multiple charges of rape of an intoxicated victim, first-degree burglary and oral copution of an intoxicated victim. He also faces charges of assault with the intent to commit a sex offense, forcible rape and grand theft.

Officials said that Alarcon-Nunez was in the US illegally, after having been voluntarily deported in 2005. It is not known when he reentered the US

Authorities said that while Alarcon-Nunez was on duty as an Uber driver, he specifically targeted parties with the intention of soliciting rides from intoxicated women. Once arriving at their homes, he then allegedly assaulted them and stole items including cell phones, computers and jewelry.

Police said that he used a Venmo app account - under the name 'Brush Bat' - to collect his Uber payments in an effort to obfuscate both his identity and his Uber records.

Dow said detectives are looking for potential witnesses and trying to determine if there are additional victims in San Luis Obispo and Santa Barbara counties northwest of Los Angeles.

At his Monday arraignment, prosecutors asked for $1.48million in bail - a significant increase from the $200,000 bail asked for at his arrest, The Tribune reported.

During a press conference Monday, Dow noted that US Immigrations and Customs Enforcement confirmed that Alarcon-Nunez is a Mexican citizen and said that he was using a 2015 California driver's license, although it was not known how long he had been residing in the US.

He is being held at San Luis Obispo County Jail.