Former New Jersey Gov. Chris Christie (R), who previously served as a U.S. attorney, told MSNBC on Tuesday that he sees the new probe into the Trump inaugural committee, and other investigations by the U.S. Attorney for the Southern District of New York, as “much more concerning” than special counsel Robert Mueller’s investigation.

In an initial interview with ABC News on Monday evening in reaction to news that the committee had been subpoenaed, Christie said the SDNY’s probes present “a much more serious threat to the administration” than Mueller’s investigation.

“I’ve always thought the Southern District of New York’s investigation was much more concerning than the Mueller investigation for a simple reason: They have tour guides and no restrictions,” he told MSNBC on Tuesday, expanding on his initial reaction. He described the “tour guides” as Trump’s former lawyer Michael Cohen and Rick Gates, who was the executive director of the inaugural committee.

“Unlike Bob Mueller who has restrictions placed upon him by the deputy attorney general when he was appointed – that his inquiry is on Russia, interference in the election, and potential Russian collusion – and you saw that Mueller reacted to those restrictions by sending the Michael Cohen matter that he discovered to the Southern District of New York. The Southern District of New York has no restrictions,” he said. “When I was a U.S. Attorney — U.S. Attorney will tell you, they call them the ‘Sovereign District’ of New York. Their jurisdiction is everywhere around the world, there will be no restrictions on SDNY.”