MSNBC host Ari Melber said there’s a prosecutor feared by many people in President Donald Trump’s inner circle. And it’s not special counsel Robert Mueller.

Many in Trump’s corner have been vocal about their dislike of federal prosecutor Andrew Weissmann, a member of Mueller’s team who has been called a “legal pit bull.” Melber said Weissmann is both tough and controversial because of three major tactics he employs:

“One, he supersizes even seemingly small offenses to play hardball. Two, he has managed to flip even hardened criminals into cooperating witnesses. And three, he charges targets that many prosecutors actually avoid, like entire corporations or defendants’ own family members. I repeat: defendants’ own family members.”

In the clip above, Melber explains why that’s so unusual ― and why it’s likely setting off alarm bells in Trump’s camp.