An audiotape of a 911 call led to Lindsay Lohan's most recent California DUI arrest .

In the tape, the mother of the actress' former personal assistant can purportedly be heard frantically pleading for help because a mysterious SUV was following her through Santa Monica.

Police later said the SUV was driven by the 21-year-old actress, who was subsequently arrested on suspicion of drunk driving and cocaine possession.

The woman contacted a Santa Monica police dispatcher at 1:34 a.m. Tuesday near 7th Street and Wilshire Boulevard, just hours after the woman's daughter had quit as one of Lohan's assistants.

Santa Monica Police Lt. Alex Padilla said the call led police officers to the Santa Monica Civic Auditorium parking lot, where they found Lohan and the woman and subsequently arrested the actress.

"We were just about to park our car. We are turning home and out of nowhere a huge white GMC came up," the woman told the dispatcher. "We're being followed by a GMC. Oh, my God, sir, they're following us. We need help."

During the nearly three-minute 911 call, the woman can be heard describing her movements through Santa Monica's downtown. The dispatcher repeatedly asked the woman where she was going. The woman eventually said, "We are heading for the police station."

"Oh, my God, what is he doing?" the woman in near hysterics yelled as the dispatcher asked what the GMC was doing.

The woman drove her black Cadillac Escalade into the Civic Auditorium parking lot, about a block from the police station, followed by Lohan driving a Yukon sport utility vehicle, police said.

"They're in front of HQ now," the dispatcher can be heard saying. "Roll somebody code. Ma'am, what's going on there? Hello? Hello? Ma'am? Hello?"

Police soon arrived at the parking lot, where the woman identified Lohan's vehicle as the one that followed her.

According to Blair Berk, her California DUI attorney, Lohan was arrested in May on suspicion of drunk driving and has twice been in rehab this year, indicated Lohan suffered a relapse.