According to an affidavit obtained by PEOPLE, when officers searched her purse, they discovered two white pills inside a sunglasses case. She allegedly told officers she did not know what the pills were, but a lab test revealed they were methylenedioxy-methamphetamine, commonly known as ecstasy or MDNA.
The affidavit also states Blac Chyna verbally abused a bartender for refusing her further service.
A British Airlines manager told police that Blac Chyna, 27, then attempted to board her flight, and became verbally aggressive toward him when the airline refused to allow her to board. She then allegedly returned to the bar, where she caused a disturbance when the bartender again refused to serve her. The bartender later told police the Blac Chyna had earlier discussed taking Xanax while sitting at the bar.
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When police arrived at the Austin airport, they say she smelled of alcohol, with officers describing her behavior as "unpredictable." They said she was "going from extremely angry, cursing at everyone then to crying."
Officers say they asked the model if she had friends or family in the area who might be able to help her, and she said no. When they asked Blac Chyna to come to their car, she dropped her weight and refused to walk. The model was taken into custody on charges of public intoxication and possession of a controlled substance. She was released from jail over the weekend, and boyfriend Rob Kardashian drove from Los Angeles to Austin to pick her up.
Blac Chyna has not responded to PEOPLE's requests for comment.
Kardashian, 28, and Blac Chyna's relationship has caused tension among his family, as she has a complicated history with the Keeping Up with the Kardashians stars. She was previously engaged to Kardashian's sister Kylie Jenner's boyfriend Tyga, with whom she shares a son. She was also once close friends with Kim Kardashian West.
On Monday, Kardashian was spotted driving his girlfriend to Epione skin care salon in Beverly Hills, where his sisters also are clients.
"Rob looked very scruffy," an onlooker told PEOPLE. "He definitely looked like someone who spent the weekend driving miles and miles across several states to pick up his girlfriend."