Actress Lindsay Lohan suffered a relapse Monday night before her early Tuesday morning arrest for misdemeanor driving under the influence and felony drug possession, according to Blair Berk, her attorney.
Berk had been monitoring Lohan's blood-alcohol level with a SCRAM monitoring device since she moved into outpatient care after a 45-day stint at Malibu's Promises Alcohol and Drug Rehab Treatment Facility. Lohan volunteered to wear the bracelet to prove that she had successfully shed her partying ways.
"Addiction is a terrible disease," Berk said in a statement released to the celebrity Web site TMZ.com. "Throughout this period, I have received timely and accurate reports from the testing companies. Unfortunately, late yesterday, I was informed that Lindsay had relapsed. The bracelet has now been removed."
Lohan was arrested early Tuesday morning after an incident involving a car chase with the mother of her personal assistant, according to the Santa Monica Police Department.
It's the second incident in less than two months in which Lohan has been investigated for driving under the influence by California police, and it happened less than two weeks after she left a rehab facility -- her second trip to rehab this year.
Lohan is reportedly back in rehab for a third time, according to TMZ.com. While the Web site did not report where the actress checked into, it was not the Promises facility.
Lohan was taken into custody near the Santa Monica Civic Auditorium, according to police, and was released several hours later after posting $25,000 bail.
Police transported Lohan to the station after she failed a field sobriety test. During a prebooking search, police found cocaine in one of her pant pockets, according to Sgt. Shane Talbot, a spokesman for the Santa Monica police.
A breath test was conducted, and her blood alcohol was between .12 percent and .13 percent, Talbot said. California's legal limit is 0.08 percent.
The 21-year-old actress was booked on two misdemeanor charges of suspicion of driving under the influence of alcohol, driving on a suspended license, and on two felony charges of possession of cocaine and transport of a narcotic, Talbot said. If convicted on the charges, Lohan likely would face jail time.
The arrest came after a chase and argument between Lohan, the driver of a white Denali sport utility vehicle, and a woman police described as the mother of the actress's former personal assistant, in a black Cadillac Escalade.
Police said the woman, who had one passenger in her car, called police around 1:30 a.m. PST to report that she was being chased by an unknown driver later identified as Lohan.
"The mother was afraid," said Lt. Alex Padilla, of the Santa Monica police. "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 chasing her, Padilla said.
It's unclear why Lohan was giving chase, according to Padilla, who did not immediately release the woman's name. The personal assistant had quit her job working for Lohan only hours before, Padilla added.
Police said the personal assistant's mother, followed by Lohan, drove into the parking lot of a civic center just a block away from the police department.
Authorities met the vehicles in the parking lot, where they witnessed Lohan and the woman in "heated debate," Padilla said. Lohan and the woman each had two passengers in their respective vehicles.
The actress recently completed a 45-day program at the Promises facility, where she checked in after crashing her Mercedes in May.
Late last Thursday, Lohan went to the Beverly Hills Police Department to be fingerprinted, photographed and booked on a suspicion of driving under the influence tied to that accident. She had an Aug. 24 court appearance in connection with that case, for which she also faces a misdemeanor hit-and-run charge.
Lohan's blood-alcohol level during the May crash was above the legal limit, according to police. Lohan and two other adults were in her car when she lost control and crashed into a curb on Sunset Boulevard, police said. The actress left the scene of the crash in another car to treat minor injuries at the hospital.
Leslie Sloan Zelnik, Lohan's publicist, said the actress would voluntarily wear the alcohol monitoring bracelet after she left rehab.
"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 in a statement at the time.
An assistant to Zelnick told ABC News that the publicist was serving jury duty and was not available for comment.
Padilla said he wasn't sure if Lohan was wearing the device when she was stopped Tuesday morning.
Lohan had been expected at a taping of "The Tonight Show with Jay Leno" to promote her film "I Know Who Killed Me," which opens Friday.
It's unclear exactly how this latest episode may affect Lohan's acting career, but it's unlikely to help. Already, her unpredictable behavior has caused on-set problems.
A year ago, James G. Robinson, CEO of Morgan Creek Productions, wrote Lohan a letter threatening legal action against her for acting like a "spoiled child" and her "irresponsible and unprofessional" behavior.
In it, Robinson writes that despite Lohan's repeated claims of illness for missing work, the production company knew about her continual partying. "We are well aware that your ongoing all night heavy partying is the real reason for you so called 'exhaustion,'" Robinson wrote. "We refuse to accept bogus excuses for your behavior."
Michael Lohan, the actress's estranged father who recently completed a two-year DUI prison sentence, told TMZ.com that he took some blame for his daughter's string of police run-ins involving cars, alcohol and drugs. He also said he wanted to put a stop to his bitter custody battle with Dina Lohan involving the couple's two younger children so the family can rally behind the struggling star.
"I want to withdraw everything -- courtwise -- sit down with Dina as Lindsay's parents and figure out how to help her," Michael Lohan told TMZ.com. "Lindsay can't do this on her own. … When we were together, none of this was happening."
Lohan's father also said shortly after his daughter's May incident that she suffers from various addictions, including alcohol and the painkiller OxyContin.
Information from The Associated Press was used in this report.