https://www.siliconvalley.com/2021/05/17/doj-reportedly-tried-to-unmask-rep-nunes-twitter-critic/

The Justice Department was investigating threatening messages related to a parody Twitter account — @NunesAlt — that criticized Rep. Devin Nunes, in a previously unknown criminal investigation, according to federal court records made public on Monday.

Twitter, in its fight to keep the user’s information secret, suggested the subpoena may be part of a government attempt — from either Nunes, a California Republican, or the Justice Department — to unmask Nunes’ critics and chill their speech.