And Hilton apparently already has a defense, according to TMZ: The purse in which the Bolivian marching powder was found isn't her's.
It all started about 11:30 p.m. on the Las Vegas strip when a motorcycle officer reported smelling marijuana smoke coming from the black Cadillac Escalade in which she had been riding, according to reports.
A subsequent search of a purse turned up the coke, which police say they tested.
Boyfriend Cy Waits, 34, was booked on suspicion of driving under the influence of drugs. The 29-year-old Hilton was released Saturday.
She was previously arrested during World Cup festivities in South Africa for allegedly possessing marijuana but was subsequently let go when a friend took responsibility for having the drug. It happened again in France last month when she was arrested for allegedly holding pot but was later released.
In 2007 Hilton served time for drunk driving.