Boston Police Commissioner William Gross ripped into ACLU "paper warriors" for suing the city over a gang database, saying the civil rights advocates are turning a blind eye to "atrocities" committed by gang members.

The ACLU of Massachusetts is suing the Boston Police Department for access to its gang database. The ACLU argues police are too secretive about how they track believed gang members, according to the organization's lawsuit filed in Suffolk Superior Court.

Gross is named as a defendant in the lawsuit.

"No ACLU present when we have to explain to a mother that her son or daughter was horribly murdered by gang violence," Gross wrote in his private Facebook post, which was obtained by the Boston Herald.

Gross referenced in the private post that the department has 22 youth programs working together to curb gang violence, and that the ACLU is conspicuously absent from those efforts.  

"I sure as hell didn't see the ACLU in El Salvador working to find a solution to our youth being inducted into the MS-13 gang ...," he wrote, saying he did travel to MS-13’s homeland and "took a hell of a risk while doing so."

The ACLU said in response to Gross' Facebook post that it was "an attempt to divert attention" from the lawsuit.