Keyshawn Johnson has thrown a flag on Justin Bieber.
As previously reported, police responded to calls from Bieber's neighbors Sunday night after the singer was accused of ONCE AGAIN driving like a manic around town.
And, according to TMZ, it was actually Johnson - a former top NFL Draft pick and current ESPN analyst - who initially took issue with Bieber's dangerous antics.
Insiders say Keyshawn left a party Sunday night inside he and Justin's gated Calabasas community when Bieber went flying by in his Ferrari.
Johnson allegedly took the child that had been riding with him home… chased after Bieber in his Prius… and then blocked JB in his driveway once the duo arrived at Justin's residence.
Bieber responded by fleeing inside and refusing to confront the ex-wide receiver, who does stand 6'4" and weigh 212 pounds.
TMZ sources add that at least two people called the police on Bieber that evening and several witnesses can confirm he was behind the wheel.
Some told officers that he looked stoned while driving.
UPDATE: Sounds like Johnson isn't the only one having problems with Bieber these days.