Sotelo was the driver of a rental car, but not the renter of said car. Her passenger also was not the renter, and neither of them were listed as authorized drivers (although her passenger would later claim to know the renter...). They were stopped by the State Police for a traffic violation.
The trooper contacted the rental car company, who asked him to tow the car. He did so. There were some giftwrapped packages in the car, which Sotelo claimed were presents that she was going to give her daughter. Although Sotelo and her companion were allowed to leave, they were not allowed to take the packages because the trooper wanted to have a K9 do a "free air sniff" on them first (I don't know why he's trying to screw up K9 sniffs for the rest of us). Ninety minutes later (!), a dog alerted on the packages. Instead of letting Sotelo take them, he got a search warrant.
They contained so much marijuana that it's even illegal in Colorado.
At trial, Sotelo moved to suppress the marijuana, arguing that the search of the car and the search of the packages both violated her Fourth Amendment rights. The people argued that since she was an unauthorized driver of the rental car, she did not have standing to challenge a search of the car (this issue remains undecided in Colorado, but the majority of courts agree with that proposition. The reasoning behind it is that you can't vicariously invoke someone else's Fourth Amendment rights in order to suppress evidence that you don't yourself have a reasonable expectation of privacy in, and the reasonable expectation of privacy in a rental car rests with people who are authorized to possess it). The court suppressed the evidence, and the people filed an interlocutory appeal.
The Colorado Supreme Court declined to decide whether or not an unauthorized driver has standing to challenge the search of a car, but held that Sotelo did have a reasonable expectation of privacy in her property within the car (namely, the giftwrapped packages which she had made no bones about claiming as hers). Accordingly, she had standing to challenge that search whether or not she could challenge the search of the car. The lower court's suppression order was affirmed.