Roger Stone, a longtime political consultant and former aide to President Trump, believes Trump would be "signing his own death warrant" if he selects former Sen. Joe Lieberman to head the FBI and replace James Comey.

Stone told NewsmaxTV Friday that Trump will have "lost leave of his senses" if he taps Lieberman, 75, for the post. Stone believes Ray Kelly, the former NYPD commissioner, is the man for the job.

"If the president nominates John McCain's best friend Joe Lieberman [as] FBI director, he's lost leave of his senses," Stone said. "Now, Joe Lieberman's a friend of mine. I like him. He's a neo-con, and he is not right for this job. We need someone who's not part of the Washington establishment. We need someone the president knows and knows well. That's why I believe former New York Police Commissioner Ray Kelly would be the best man for this job."

"If the president appoints Lieberman, he will be signing his own death warrant," Stone said.

Lieberman emerged on Thursday as the top candidate for the job. While he's received support from Republicans, backing from Senate Democrats has been hard to come by.

A longtime Democratic senator, Lieberman was the party's vice presidential nominee in 2000 and ran for the party's nomination in 2004. However, he won his final term in 2006 as an independent and endorsed Sen. John McCain, R-Ariz., for president over then-Sen. Barack Obama in 2008.