The US government dropped its effort to force Twitter to identify the owner of an anti-Trump account purported to voice dissent from federal employees, court documents showed Friday.
In a court filing, Twitter sought the dismissal of the lawsuit it had filed just a day earlier that claimed the government had overstepped its authority in seeking to unmask the account owner.
Twitter's filing said the summons requesting the name or names of the account holder had been withdrawn.
A Justice Department official confirmed the investigation -- details of which had not been disclosed -- had ended.
The lawsuit revealed that the Department of Homeland Security and US Customs and Border Protection had sought the unmasking of the @ALT_USCIS account holder who has been criticizing President Donald Trump's administration.
The American Civil Liberties Union welcomed the government's decision to back down, tweeting: "Big victory for free speech and right to dissent."
Twitter's lawsuit in California could have touched off a contentious battle with the government over digital privacy and the right to anonymous free speech.
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.
It is one of several "alternative" handles apparently created by government workers after Trump's inauguration in January that have sometimes revealed data the new administration sought to suppress or remove from official websites.
"The rights of free speech afforded Twitter's users and Twitter itself under the First Amendment of the US Constitution include a right to disseminate such anonymous or pseudonymous political speech," the lawsuit said.
Twitter's lawsuit noted that "those who speak through these 'alternative agency' accounts do so pseudonymously, often going to considerable lengths to avoid disclosing their real identities" for fear of retribution.