But some of the people who posted comments seemed emboldened by Facebook’s freewheeling atmosphere. “Let them kill each other,” wrote one of the Facebook members who posted comments under a name that matched that of a police officer.“Filth,” wrote a commenter who identified himself as Nick Virgilio, another participant whose name matched that of a police officer. “It’s not racist if it’s true,” yet another wrote.The officers were at times spurred on by civilian supporters and other city workers, including members of the Fire Department, an analysis indicated.It is impossible to say with certainty whether those quoted are the people they claim to be. But a comparison by The Times of the names of some of the more than 150 people who posted comments on the page with city employee listings showed that more than 60 percent matched the names of police officers, and Mr. Browne did not deny that they were officers. Of course, some people do circumvent Facebook’s rule on identification.It was impossible to determine the racial breakdown of the officers who were posting comments, but at least one of the participants said that most of them seemed not to be minorities.