A New York City police officer was arrested for participating in the motorcycle gang attack

A few days ago I posted an article stating that a New York City 'undercover' police officer was at the scene of the beating of an Asian man by members of a motorcycle gang (please refer to the next article).

At that time many people felt that the officer was justified in not trying to help the man who was being beaten, because the officer would have blown his cover (revealed his secret identity).

Now, however, it looks as if the undercover police officer not only refused to help Mr. Lien, but he also participated in the attack against Mr. Lien by smashing his helmet against one of Mr. Lien's windows.  This officer has now been arrested.

The article:

http://news.yahoo.com/undercover-nypd-suv-biker-attack-193030746.html

Vocabulary from the article:

undercover police officer - a police officer who pretends to be a member of a group that is being investigated

to be justified - if someone is justified in doing something, what he did is considered right or acceptable

to be arrested - this is when the police suspect you have committed a crime and they take you into custody (to the police station)

an SUV - a Sports Utility Vehicle. Basically a really big car

allegedly - this means something hasn't been proved yet, but it looks as if someone is guilty of something

a mob - a disorderly group

subsequent - following

to be charged with a crime - this is when the police officially state the crime a person is accused of and the person is then processed through the criminal justice system based on this alleged crime

charged with riot - I think this is a mistake.  It should be: charged with rioting

mischief - when you do something wrong for the fun of it

the veteran detective -  the experienced detective

banging - hitting something hard

clipped the biker  - hit the rider obliquely, just barely hit the biker

NYPD Commissioner - the leader of the New York Police Department

modified duty - his duties have been changed so that he is kept inside in an office

pending the outcome - until the outcome of an investigation by Internal Affairs (they investigate police misconduct)

a badge - a piece of metal that identifies the officer as a member of the police department

murky, murkier - less clear

blowing their cover - revealing their real identity as police officers when they are supposed to be keeping it secret

compromising his identity - ruining the false identity he had established could compromise (ruin) all the work he had done undercover