May 31, 2007, 13:00 GMT
Lindsay Lohan's arrest could ruin nights out for the rest of Hollywood's underage drinkers.
04/29/2007 - Lindsay Lohan - The 2007 Coachella Festival - Empire Polo Field - Indio, CA © Solarpix / Photorazzi
The 20-year-old actress was charged with DUI (driving under the influence) after she crashed her car on Saturday night (26.05.07) after partying at Los Angeles' Les Deux club and the Sky Bar at the Mondrian hotel until around 5am.
The legal drinking age in the US is 21 and alcohol cannot be served in California after 2am, and police have now vowed to clamp down on law breakers.
John Carr, spokesman for the California Department of Alcoholic Beverage Control, said: "We have a duty to check on these things whenever there's a report of a minor involved in a crash. Underage drinking is a huge problem in the state of California."
Lindsay - who turns 21 on July 2 - is a regular at all of Hollywood's trendiest night spots including Les Deux, Teddy's and Hyde.
Carr revealed an undercover investigation has been launched to determine whether the 'Just My Luck' star was served alcohol in any of the establishments she visited the weekend of the crash, and if she, or any of her friends, were served after hours.
Les Deux spokeswoman Marissa Knies insists Lindsay had dinner and didn't drink.
Knies said: "Because of the enormous paparazzi presence outside of Les Deux that night, we allowed her to stay late and wait for her friends."
A video shows Lindsay leaving at 3.30am.
Teddy's at the Roosevelt Hotel paid a $3,000 fine on May 4 for accusations made last year that they sold contaminated beverages and sold alcohol after hours.
There is also an investigation pending against Club Mood, another popular hang out for Lindsay, Paris Hilton and other stars.
Meanwhile, Lindsay's father has claimed his daughter suffers from multiple addictions, including a dependence on alcohol and the painkiller OxyContin.
Michael - who has served jail time for DUI and assault convictions dating back to 2005 - said: "I spoke to the people treating Lindsay, because I wanted to make sure she was getting the right care. And I'm satisfied they are doing the right thing for her, helping her detox from the painkillers and other things. That's a very important step."
Lindsay checked into Malibu's Promises rehab centre on Monday (28.05.07) where she is set to stay for a month of intensive treatment.
Police found a "usable amount" of cocaine in her car after Saturday's crash.
(C) BANG Media International
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