President Trump on Sunday threatened to investigate former Gov. Chris Christie of New Jersey over a 2013 political scandal, days after the F.B.I. raided the home and office of another former Trump official turned critic.

Mr. Trump made the threat on social media after Mr. Christie said during an appearance on ABC News that the president “doesn’t care” about maintaining a separation between his office and criminal investigations.

Mr. Christie, a Republican who was a federal prosecutor before he was elected governor, had been discussing Mr. Trump’s connection to recent F.B.I. searches of the Maryland home and Washington office of John R. Bolton, a national security adviser in the president’s first term.

The raid of Mr. Bolton’s home and office last week was the latest example since Mr. Trump returned to office of how his administration is deploying the Justice Department as a weapon for the president’s score-settling and political crusades.

Mr. Trump wrote on his Truth Social platform late Sunday that Mr. Christie had lied about 2013 lane closures on the George Washington Bridge “in order to stay out of prison, at the same time sacrificing people who worked for him.” The president was referring to a decision by Mr. Christie’s associates to close access lanes to the bridge, which links New Jersey and Manhattan, in order to punish the Democratic mayor of a New Jersey town.

“Chris refused to take responsibility for these criminal acts,” Mr. Trump wrote. “For the sake of JUSTICE, perhaps we should start looking at that very serious situation again? NO ONE IS ABOVE THE LAW!”

The 2013 “Bridgegate” closures created days of traffic jams, and the scandal tarnished Mr. Christie’s reputation and helped to destroy his 2016 presidential candidacy. Mr. Christie has long denied any knowledge of the plan. He could not immediately be reached for comment.

Mr. Trump and Mr. Christie, who have known each other for decades, once had a good relationship. Mr. Christie initially served as the head of Mr. Trump’s first presidential transition team, and he helped Mr. Trump with debate preparations in the run-up to the 2020 election.

But their relationship soured after Mr. Trump refused to concede the 2020 election to Joseph R. Biden Jr. When Mr. Christie ran for president again last year, he was the most vocal Trump critic in the Republican primary field.

In 2016, two of Mr. Christie’s associates were convicted of wire fraud and other federal charges for their roles in the bridge closure, but the Supreme Court unanimously overturned the convictions four years later. Mr. Trump said at the time that the court’s decision was a “complete and total exoneration” of Mr. Christie, who was not charged in the case, “and all others involved.”

It was not immediately clear what aspect of Mr. Christie’s Sunday appearance on ABC’s “This Week” had led Mr. Trump to threaten him on social media.

Mr. Christie mentioned the president by name after he was asked by the journalist Jonathan Karl whether Vice President JD Vance, who has defended the criminal investigation into Mr. Bolton, is playing a role in it.

Mr. Christie responded by mentioning what he called the administration’s disregard for the idea of separation between the president and criminal investigations. He noted that Mr. Trump had recently described himself as the nation’s “chief law enforcement officer.”

“Donald Trump sees himself as the person who gets to decide everything, and he doesn’t care about any separation,” Mr. Christie told Mr. Karl. “In fact, he absolutely rejects the idea that there should be separation between criminal investigations and the politically elected leader of the United States. This is much different than it’s ever been run before.”

He said Mr. Trump had telegraphed this approach during his 2024 presidential campaign.

“He told you he was going to do this, that he was going to have a Justice Department that acted as his personal legal representation, and that is what they’re doing,” Mr. Christie said.

The search of Mr. Bolton’s Maryland home and Washington office came days after Mr. Trump attacked him for criticizing his approach to Russia’s invasion in Ukraine. Mr. Bolton was pushed out of the first Trump administration in 2019, after he disagreed with the president on several foreign policy challenges.