The troubled saga of Lindsay Lohan took another turn early Tuesday when police booked her for investigation of drunken driving and cocaine possession after a frightened woman dialed 911 to report being chased by Lohan's SUV.

Less than two weeks out of rehab, with another drunken-driving case pending, Lohan had a blood-alcohol level of between 0.12 and 0.13 percent when police found her about 1:30 a.m., Sgt. Shane Talbot said.

Lohan attorney Blair Berk said her client had relapsed and was again receiving medical care.

"Addiction is a terrible and vicious disease," Berk said Tuesday.

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Authorities received a 911 call from the mother of Lohan's former personal assistant, said Lt. Alex Padilla. The assistant had just quit hours before, he said.

"The mother was afraid," Padilla said. "She wasn't quite sure what was going on so she called the police saying she wanted to make sure everything was going to be OK."

The woman apparently didn't realize it was Lohan who was behind her, Padilla said.

Police said the woman drove her black Cadillac Escalade into the parking lot of Santa Monica's Civic Auditorium, about a block away from the Santa Monica Police Department, followed by Lohan driving a Yukon sport utility vehicle. Authorities arrived and saw Lohan and the woman in "heated debate," Padilla said. Two males were with Lohan in the 2004 Yukon, including the owner of the vehicle, Padilla said. The mother had just one passenger and it wasn't her daughter, Padilla said, correcting earlier police statements.

Padilla said the 21-year-old Lohan was unable to walk a straight line, touch her nose or follow a small light with her eyes. Officers also detected the smell of alcohol, Padilla said.

The movie star was booked for investigation of driving under the influence and driving on a suspended license, both misdemeanors, and possession of cocaine and transport of a narcotic, both felonies, authorities said.

During a pre-booking search, police found cocaine in one of Lohan's pants pockets, Talbot said.

Several hours later, Lohan was released on $25,000 bail.

Padilla said he didn't know why Lohan was trying to catch the woman, whom he didn't name.

Last week, Lohan turned herself in to Beverly Hills police to face allegations of driving under the influence in connection with a Memorial Day weekend hit-and-run crash.

Lohan lost control of her 2005 Mercedes SL-65 convertible and crashed into a curb and shrubs on Sunset Boulevard, police said. Lohan's blood-alcohol level at the time of that crash was above the legal limit, authorities said, but they wouldn't disclose how high it was. She also faces a misdemeanor charge of hit and run in that case.

A court date was scheduled in that case for Aug. 24.

Lohan left Promises Malibu Alcohol and Drug Rehab Treatment Facility on July 13, after a stay of more than six weeks. She had also checked into rehab for substance abuse treatment in January.

When she left, publicist Leslie Sloan Zelnik said Lohan would voluntarily wear an alcohol-monitoring bracelet.

"In part she is wearing the bracelet so there are no questions about her sobriety if she chooses to go dancing or dining in a place where alcohol is served," Zelnik said at the time.

After bailing her out Tuesday, Berk said Lohan had been tested daily in order to support her sobriety.

"Throughout this period, I have received timely and accurate reports from the testing companies," Berk said. "Unfortunately, late yesterday I was informed that Lindsay had relapsed. The bracelet has now been removed. She is safe, out of custody and presently receiving medical care."

Lohan's estranged father, Michael Lohan, said he was worried about his daughter even though theirs was a "troubled relationship." In a statement issued through his New York attorney, he also suggested he and his wife Dina rally to help her, putting their own "legal battle aside for the good of our children."

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