A lawyer for Rep. Devin Nunes (R-CA) told a Virginia judge on Friday that they’ve reached a “dead end” in their quest to identify the authors of popular parody accounts poking fun at the GOP congressman. The attorney, Steven Biss, made the admission while insisting that Twitter should be forced to release the identities of the people behind the accounts—“Devin Nunes’ Cow” and “Devin Nunes’ Mom”—so he could serve them with lawsuits and push his defamation case forward. The accounts are at the center of a lawsuit Nunes filed against the social-media giant, alleging he was defamed on Twitter by the two accounts and Republican political strategist Liz Mair. The company has argued it’s not liable for content posted by other individuals.

“They’re doing more than allowing Liz Mair, the cow and the mom to post a tweet,” Biss said in court, according to The Fresno Bee. “They’re censoring, they’re promoting an anti-Nunes agenda, they’re banning conservative accounts and they’re knowingly encouraging it.”