Wojciech Braszczok, a 10-year veteran of the NYPD, was arrested Tuesday night. The 32-year-old undercover detective spent much of his career in narcotics, but he recently transferred to another division.
Braszczok was under investigation because he did not immediately report that he witnessed the beating of Alexian Lien. But now authorities say they have video of Braszczok being an active participant in the confrontation.
Investigators say Braszczok is seen on video punching the rear window of the SUV, while his attorney says video shows the detective at least 12 feet away when the SUV driver was attacked.
Braszczok left the courthouse after posting the $150,000 bond set by the judge.
Clint Caldwell, who is accused of helping pull Lien out of the Range Rover and beating him, will also be in court Wednesday to face charges of gang assault and criminal mischief. He was the sixth biker to be charged in the case.
But even with several arrests made, investigators are still looking for more people. The district attorney's office says it is scrutinizing all the evidence to build the strongest possible cases to hold those responsible accountable.
WABC-TV, ABC News and The Associated Press contributed to this report.