Senator threatens Musk: Fix your companies or Congress will

• "I’m asking for answers from [Elon Musk] who is putting profits over people and his debt over stopping disinformation," Markey tweeted on Friday.

Musk's response came Sunday, saying on Twitter: "Perhaps it is because your real account sounds like a parody?"

• "And why does your pp have a mask!?," he added in a follow up tweet, referencing the senator's Twitter profile picture, showing him wearing a surgical mask.

Markey shot back Sunday afternoon, telling Musk: "One of your companies is under an FTC consent decree. Auto safety watchdog NHTSA is investigating another for killing people."

• "And you’re spending your time picking fights online. Fix your companies. Or Congress will," he added.

Catch up quick: A Washington Post reporter wrote on Friday that he was able to quickly and easily set a verified account impersonating Markey, having previously gotten the senator's permission to conduct the test.

• The test account was created before Twitter paused signups for Twitter Blue on Thursday, as impersonation accounts flooded the platform, per the Post.

In his letter to Musk, Markey demanded answers to a series of questions about Twitter's verification process by Nov. 25.

• "Allowing an imposter to impersonate a U.S. Senator on Twitter is a serious matter that you need to address promptly," Markey wrote.

Worth noting: Markey sits on the Senate Commerce, Science and Transportation Committee, which oversees the Federal Trade Commission (FTC) and the National Highway Traffic Safety Administration (NHTSA).

Go deeper: Elon Musk's major Twitter miscalculation

Editor's note: This story has been updated with new details throughout.