When authorities searched Bieber's California home earlier this month, a deputy found suspected illegal drugs at the bedside of Bieber house guest Lil Za, who now faces a felony drug charge. But a detective who searched other parts of the home told CNN last week that he saw "no sign of drugs" there.
Bieber hasn't been charged with any drug-related crimes in connection with either case.
But if drugs were involved, that could change the equation when it comes to immigration issues, experts say.
"He may have a difficult time returning to the U.S. after traveling," Padilla said. "If there is a conviction on the use of marijuana, he may run into some issues when renewing his visa or even attempting to apply for residency."
And if authorities add a drug charge into the mix, that could eventually put deportation on the table, said Ira Kurzban, an attorney in Miami who wrote a widely used reference book on immigration law.
"Deportation grounds for drug-related crimes are broadly defined," Kurzban said. But a drunk-driving charge that isn't drug-related, he said, "is not a basis to deport somebody."
Decision near on Bieber's egging charge; singer takes it easy in Panama
A double standard?
Bieber was released Thursday from a Miami jail an hour after he made a brief appearance through a video link before a judge, who set a $2,500 bond that afternoon.
Since his arrest, some critics have wondered whether Bieber wouldn't be deported for reasons that have little to do with the law.
In a CNN.com opinion column last week, CNN contributor Ruben Navarrette suggested the wealthy singer's star status might be getting him special treatment.
"Bieber has an estimated net worth of about $130 million," Navarrette wrote. "I bet that, right about now, many of those Mexican immigrants who were deported because they came to the attention of local police officers for a burned-out taillight, or for not making a complete stop at an intersection, are wishing that they had been a rich, white kid with marginal music ability and too much money. If so, things might have gone differently for them."
But Padilla says there's a key difference between such examples and Bieber's case: He has a visa.
"The reason an individual who had failed to stop at a stop sign or is driving without a license comes in contact with immigration authorities is because they're undocumented," Padilla said. "You're not comparing apples to apples."