philtons072310_01.jpgPolice pulled over a car in which Paris Hilton was riding Friday night on the Vegas Strip because officers smelled marijuana smoke coming from the vehicle. During a search of the car and the passengers' possessions, police found an undisclosed amount of cocaine in Hilton's purse, according to the AP.

Hilton was booked around 2 a.m. for possession of cocaine and released.

A source close to Hilton tells X17online.com exclusively, "Paris was borrowing a friend's purse because it matched her outfit better than the ones she brought with her to Vegas. She didn't realize there was anything left inside the bag -- the amount of drugs was so small she didn't even see it because it was in a small pocket inside the purse."

Hilton has faced other drug charges in recent months -- in July she was detained in South Africa for alleged marijuana possession but charges were later dropped with police determined the drugs were not Paris'. A few weeks later reports claimed, as Paris traveled to Corsica, a customs official found a gram of marijuana in Hilton's purse though Paris denied the stories via her Twitter.

Our source tells us Paris is again upset that she has again been unfairly associated with drugs: "Paris is mad because she's being blamed for a friend's mistake."

Paris went to Las Vegas with her boyfriend, Cy Waits (owner of Vegas nightclubs XS and Tryst and Drai's in Hollywood), yesterday after a man was arrested trying to break into her house earlier this week. It was reported yesterday that Waits held the intruder at gunpoint before police arrived. Waits was arrested and booked on a DUI charge last night as well.