Customs officials requested the airport's tower hold the plane at 3 p.m. on the tarmac.
A source close to the airport tells ABC News federal agents with U.S. Customs and Border Protection decided to admit Bieber to the U.S. more than five hours later.
Bieber was stopped on suspicion of marijuana.
Trained drug-sniffing dogs aided in the search of Bieber's luggage and the pop star was interviewed at length before it was decided to admit him.
If contraband had been found on the plane, it would have been turned around.
This comes just days after a police report was released accusing the pop star of being under the influence of alcohol, pot and Xanax when police stopped him for allegedly street racing in Miami beach last week.
Bieber was also booked on an assault charge in Canada this week.
He's accused of hitting a limo driver in Toronto a month ago.
Those incidents have led thousands of people to petition the White House to deport the pop star.
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