Justin Bieber's streak of bizarre and bad behavior continued this week, this time in the Hamptons.

Bieber and his crew are being blamed for a brawl in the South Pointe nightclub -- but the 'Beauty and a Beat' singer may not be the one legally responsible for the alleged beatdown.

TMZ reports that Bieber, 19, and his crew were sipping on booze in the VIP area of the Southampton hotspot when a girl in the club tried speaking with the boy wonder. When she was denied, she got her big mean ole boyfriend (or just some guy, who knows?) to intervene, and that's when things got ugly.

The man allegedly angrily approached Bieber, who flipped out, ripping his own shirt off and screaming at the man. Before things got too messy, Bieber and his posse left the club, but they didn't leave the parking lot fast enough, and more trouble broke out.

It's unclear exactly what happened, but Bieber, who was inside his waiting SUV at the time, reportedly jumped out from the sunroof onto the hood of the vehicle -- and the man involved ended up knocked out on the cement, eventually requiring hospitalization.

It's also unclear who started the physical altercation, because both Bieber's crew and the alleged victim were said to have been aggressive in the fight.

This is far from the first time Bieber's been fingered in a fight case. At least this time he didn't spit in anyone's face ... yecch.

An investigation has been opened in the case, though sources insist it's not Bieber, but his beloved, oft troublesome crew, who are being looked at as suspects.

See what happens when Selena Gomez is busy?