'They’re coming for Roger Stone’: Former prosecutor explains what Mueller may have on Trump's fiery ally

Yet another associate of conservative provocateur Roger Stone has been subpoenaed by the special counsel Robert Mueller's investigation, according to a new report from Reuters on Friday. Former federal prosecutor Paul Butler explained on MSNBC that this fact builds the case that Mueller's team has something on Stone, an ally of President Donald Trump.

"They're coming for Roger Stone," Butler told "The Beat" host Ari Melber Friday evening. "He's been a shady character from day one in this investigation."

Butler noted that Stone has suspicious ties to WikiLeaks founder Julian Assange, who is believed to have facilitated the released of Russian-hacked emails stolen from the Democratic National Committee and Hillary Clinton's campaign Chair John Podesta during the 2016 campaign.

At the time, Butler said, "Roger Stone knows all about what's coming out before the hacked emails are released. He's going all over the media and Breitbart predicting that some dirt is coming out on Hillary. How does he know this? He's been inconsistent about his relationship with WikiLeaks. At times he says he knows Julian Assange, at times he says he doesn't know him. ... Then, the day after the election, Ari, there's that bizarre tweet from WikiLeaks to Roger Stone: 'Now we're free to talk.' Really fishy, Mueller's got to investigate that."  (Note: The correct quote from WikiLeaks to Stone, reported by the Atlantic, is "Happy? We are now more free to communicate.")

Sam Nunberg, another close associate of Stone's has also been subpoenaed and testified for Mueller's team. Nunberg, too, though that Mueller intends to go after Stone.

Watch the clip below: