Since Roger Stone was indicted by special prosecutor Robert Mueller, President Donald Trump has been steadfast in denying that Stone has any evidence of him being involved in Stone's alleged wrongdoing.

While the media has tended to credulously report Trump's denials, that doesn't carry much weight with Jessica Roth, a former federal prosecutor with the Southern District of New York.

On Friday, Roth spoke to NBC News' Peter Alexander about the connection between Roger Stone and Donald Trump—and said Trump shouldn't automatically be trusted when he makes an "ironclad" denial.

"I just don't think we can put much stock in this," she said. "He is what we would call an unreliable witness in so many ways. Whether it's the size of the inauguration crowd or what his lawyers said before Congress."

When Trump said his lawyers have told him he's "not a target," Roth said she doesn't necessarily believe that's true.

"I would not give too much credit to his account to what he says his lawyers said to him," she said.

"He often contradicts himself in real time, so it is hard to really keep up with him," added New York Times reporter Annie Karni. "Pinning him down on a real answer is always very difficult."

Watch the clip below or here.