Twitter has filed a lawsuit against the Department of Homeland Security, asking the court to prevent the agency from unmasking the user behind an account critical of the Trump administration.

By Hayley Tsukayama @ The Washington Post, 1 hour ago

....According to Twitter's court filings, Homeland Security is “unlawfully abusing a limited-purpose investigatory tool” to find out who is behind the @ALT_USCIS account. Its Twitter feed has publicly criticized the administration's immigration policies, particularly the actions of the U.S. Citizenship and Immigration Services (USCIS) division of Homeland Security.....

Tweets from the @ALT_USCIS account, which is still active, indicate that it is run by someone who claims to be a government employee working at the USCIS. According to the department's policy on personal social media use, employees cannot post anything that could "cause damage to the department's reputation or bring it into disrepute."  The account's description, however, stresses that its views are “Not the views of DHS or USCIS.” As of the time of the court filing, the account had been active for two months and amassed more than 32,000 followers.....