Paris Hilton, who was arrested over the weekend on suspicion of cocaine possession, is claiming that the drugs found in handbag were obtained illegally and are therefore inadmissible as evidence.

Hilton, 29, was arrested Friday when .8 grams of “cocaine in a clear baggy” fell from her purse after police reported smelling marijuana emanating from the Cadillac Escalade her boyfriend Cy Waits was cruising down the glitzy strip. She will be charged with possession of a controlled substance, a low-level felony. Under Nevada law, Hilton’s sentence could include probation to up to four years in prison. The former Simple Life star could also be fined up to $5,000.

However, the heiress is hanging her designer handbag on the hope that her search will be deemed unlawful, making any evidence obtained during it “fruit of the poisoned tree” — as the Legal Eagles would say — and therefore inadmissible in court.

“Cops discovered the cocaine inside the security offices where Paris was taken. Because Paris was taken away from the scene where the car was pulled over, this could potentially be an illegal search of a person,” a source reveals. “Las Vegas Metro didn’t follow standard procedures when Paris was arrested and her lawyer will be talking to the District Attorney about this.”

After the cocaine discovery, Paris told Vegas cops that the purse did not belong to her and said she had borrowed it from a friend. When asked the drugs were hers, Hilton allegedly told police “she had not seen it but now thought it was gum.” Since we all know how often gum is packaged in a clear baggy. (Insert eye-rolling here.)

“Paris says she changed the purse she was carrying at the last minute because the one she had didn’t coordinate with the rest of her outfit the way she wanted. She says she borrowed a friend’s purse because it matched better.”

Hilton will be arraigned on Oct. 27.