Dan Scavino, the White House social media director, broke the law when he lambasted a Congressman on social media, the Office of Special Counsel said in a letter today.

In April, Scavino tweeted that House Republican Justin Amash “is a big liability,” and he encouraged Trump supporters to defeat Amash in a primary vote.

.@realDonaldTrump is bringing auto plants & jobs back to Michigan. @justinamash is a big liability.#TrumpTrain, defeat him in primary. — Dan Scavino Jr. (@DanScavino) April 1, 2017

Some observers suggested the tweet, although innocuous by some examples from the current administration, may have violated a law called the Hatch Act. The act, from 1939, bars government officials from using their positions for campaigning purposes. According to a complaint filed with the White House Office of Special Counsel by the left-leaning watchdog group Citizens for Responsibility and Ethics in Washington, Scavino’s tweet crossed the line.

There were some questions, however, about how the law should be applied in the digital age. The tweet was sent on a Saturday, and from a personal account, muddying whether it was sent in an official White House capacity.

In its response to CREW, the Special Counsel’s Chief of the Hatch Act argued that it was a violation, and the office said it had sent a warning letter to Scavino, who was recently counseled on the issue. The office said it had not found any other violations on Scavino’s Twitter account, but wrote that, if it does, it “will consider such activity to be a willful and knowing violation of the law.”