The account in question is purportedly run by one or more current employees of the US Citizenship and Immigration Services (USCIS), a unit within Homeland Security.
In March, the DHS summoned Twitter to release the names of the users behind the @ALT_USCIS account.
As a result, Twitter is withdrawing a federal lawsuit that challenged the government's request. Though a number of such alternate accounts are in action by the government employees, but this is the first one which has received the dubious privilege of a government investigation.
The Department of Homeland Security, which oversees the immigration agency and was named as a defendant in Twitter's lawsuit, didn't immediately respond to requests for comment. "The anonymity that the First Amendment guarantees is often most essential when people criticize the government, and this free speech right is as important today as ever".
The lawsuit, filed Thursday, contended that the customs agency was abusing its investigative power.
"Twitter's lawsuit, among other benefits, helps reinforce to its users that it has their back and it's not going to just sell them out whenever the government asks", said Eric Goldman, a professor at Santa Clara University School of Law.
The accounts claimed to represent the views of government staffers who opposed Trump's policies.
The government so far hasn't specified a reason for wanting to know the identity or identities behind the Twitter handle. Other such "alternative" - or "alt" - accounts include @Alt_CDC for the Centers for Disease Control and Prevention and @AltUSEPA for the Environmental Protection Agency.
In the now-withdrawn suit, lawyers for the company said that the government could not compel Twitter to turn over the information unless several conditions were met.
When CBP refused to drop the demand, Twitter sued, hoping to have the court rule that it is unlawful and unenforceable.
"We are very heartened that Twitter is standing up for its users and making such full-throated defense of their free-speech rights", Bhandari said.