Washington (CNN) The House Ethics Committee announced Friday it was investigating a complaint that Republican Rep. Matt Gaetz tried to threaten Michael Cohen ahead of his congressional testimony.

The day before Cohen, President Donald Trump's former personal lawyer, appeared before the House Oversight and Reform Committee in February, Gaetz tweeted something at Cohen that critics labeled witness intimidation.

"Do your wife & father-in-law know about your girlfriends? Maybe tonight would be a good time for that chat. I wonder if she'll remain faithful when you're in prison. She's about to learn a lot," Gaetz tweeted.

Gaetz, a Florida congressman who's a close ally to the President, did not offer proof or details to back up his tweet. He soon deleted the message and apologized to Cohen.

Later that week, Democratic Rep. Kathleen Rice of New York sent a letter to the House Ethics Committee asking for an investigation. Rice, a former federal prosecutor, wrote that she believes the GOP lawmaker's comments could rise to the level of witness tampering and intimidation. She later submitted a formal complaint on March 13, according to her office.

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