People close to President Donald Trump think it's likely that his longtime lawyer Michael Cohen will flip on the president to avoid a lengthy prison sentence.

The FBI raided Cohen's offices, and he is believed to be under investigation on suspicion of bank fraud and campaign finance violations.

A former assistant US attorney says most people seek to strike deals to keep themselves out of jail: "If he flips, everyone he's associated with has exposure. And I'm confident that almost certainly, there is a 'there' there."

People close to President Donald Trump keep suggesting that his longtime lawyer Michael Cohen is likely to flip, or cooperate with the government by providing information on others in exchange for a lesser punishment.

One former assistant US attorney explained to Business Insider why it seemed so likely.

Cohen and Trump have had a close relationship over the years. The lawyer has claimed intense loyalty to the president as a friend and adviser — once reportedly saying he would "take a bullet" for Trump — and handling sensitive matters for the president. That includes paying the adult-film star Stormy Daniels $130,000 days before the election to keep quiet about an affair she says she had with Trump.

But Cohen's loyalty has been tested since the FBI raided his office, home, and hotel room to obtain records and documents — including some that seem to be related to the Daniels payment. He's under investigation for possible bank fraud and campaign finance violations, The Washington Post reported.

Cohen hasn't been charged with any crimes, but the prison sentence for such allegations, if he's convicted, could be substantial, and it's rare that people face such a prospect without seeking a way out, said Mitchell Epner, a former assistant US attorney for the District of New Jersey.

"The question is when Michael Cohen started doing whatever he was doing, did he have the mental conversation with himself that 'I'm talking the talk, and if my time comes, I'm going to do my time, and then I'll go away and when it's time for me to come back, I'll come back,'" Epner, now an attorney at Rottenberg Lipman Rich, told Business Insider. "And if he made his peace with that before all of this started, then it's really simple. He will stand up for whoever he's protecting, and he will go away."

But he said there were "very, very few stand-up guys like that" when faced with prison time, for example, in excess of 20 years.

"When I was a prosecutor, there were some drug gangs that I dealt with that had stand-up guys like that," Epner continued. "When we caught them, they might plead guilty and they might go to trial, but they were never going to roll on anybody. And you knew who they were, and you could tell from the very beginning when you were talking to their attorneys: 'Don't come to us with a deal — it's not going to happen.'"

About 90% of the people Epner dealt with were looking for a deal, he said, adding that if the person hadn't had the conversation with themselves in advance about serving an extended prison sentence, it was even more likely the person would be looking to cut a deal.

"I don't know whether or not Michael Cohen is a tough guy," he said. "But when I hear things in the media like, 'How is this going to affect my family — I need to take care of them,' if he is actually asking those questions — if that's real and not fake — then it seems extraordinarily likely that he flips. And if he flips, everyone he's associated with has exposure. And I'm confident that almost certainly, there is a 'there' there."

A person who spoke with Cohen told the Associated Press that Cohen had expressed worry about his family.

Donald Trump. Chris Kleponis - Pool/Getty Images 'Without exception, a person facing a prison term cooperates'

In recent days, those close to Trump have suggested that Cohen may very well flip if faced with serious charges.

Two sources close to Trump said the president's inner circle was actively discussing such an outcome, Politico reported.

"When anybody is faced with spending a long time in jail, they start to reevaluate their priorities, and cooperation can't be ruled out," one Trump ally who knows Cohen told the publication.

The president and his allies fear that the documents seized by the FBI in the Cohen raids could cause huge problems for Trump, per Politico.

"I think for two years or four years or five years, Michael Cohen would be a stand-up guy," a lawyer who is defending a senior Trump aide in the special counsel Robert Mueller's investigation, told Politico. "I think he'd tell them 'go piss up a rope.' But depending on dollars involved, which can be a big driver, or if they look at him and say it's not two to four years, it's 18 to 22, then how loyal is he? Is he two years loyal? Is he 10 years loyal? Is he 15 years loyal?"

Jay Goldberg, an attorney who has represented Trump, told The Wall Street Journal that he spoke with Trump about Cohen and warned him not to trust his attorney if Cohen ultimately faced criminal charges.

Cohen, Goldberg said, "isn't even a 1" on a scale of 1 to 100 in which 100 would be taking "the bullet," so to speak.

Speaking with CNN's Erin Burnett on Thursday, Goldberg said he told Trump that "anybody who is facing 30 years never stands up."

"Without exception, a person facing a prison term cooperates," he said, adding however that he didn't "accept the notion of 'flip.'"

"'Flip' means to me that when faced with the potential of spending time in jail, he will tell the truth," he continued. "I don't think that was what the president was concerned about, and that's not what I'm concerned about."

Goldberg suggested that Cohen would make up information on Trump to help get himself some "leniency."

The White House has sought to distance Trump from Cohen, meanwhile. The White House press secretary, Sarah Huckabee Sanders, told reporters earlier this week that the two had "still got some ongoing things" but "the president has a large number of attorneys."

But Saturday morning, Trump sought to push back against the assertion that Cohen would flip if faced with charges, blasting a New York Times story on the subject.

Trump tweeted that The Times and its reporter Maggie Haberman were "going out of their way to destroy Michael Cohen and his relationship with me in the hope that he will 'flip.'"

The president, who dined with Cohen at Mar-a-Lago in the weeks before the raids and phoned him in the days that followed to "check in" on him, said his attorney was "a fine person with a wonderful family."

"Michael is a businessman for his own account/lawyer who I have always liked & respected," he continued. "Most people will flip if the Government lets them out of trouble, even if it means lying or making up stories. Sorry, I don't see Michael doing that despite the horrible Witch Hunt and the dishonest media!"