In the months before the FBI’s dramatic move to execute a search warrant at former president Donald Trump’s Florida home — and open his safe to look for items — federal authorities grew increasingly concerned that Trump or his lawyers and aides had not, in fact, returned all the documents and other material that were government property, according to people familiar with the discussions.

Officials became suspicious that when Trump gave back items to the National Archives about seven months ago, either the former president or people close to him held on to key records — despite a Justice Department investigation into the handling of 15 boxes of material sent to the former president’s private club and residence in the waning days of his administration…

In June, Bobb said, she and Trump lawyer Evan Corcoran met with Jay Bratt, the chief of the counterintelligence and export control section at the Justice Department, along with several investigators. Trump stopped by the meeting as it began to greet the investigators but was not interviewed. The lawyers showed the federal officials the boxes, and Bratt and the others spent some time looking through the material.

Bobb said the Justice Department officials commented that they did not believe the storage unit was properly secured, so Trump officials added a lock to the facility. When FBI agents searched the property Monday, Bobb added, they broke through the lock that had been added to the door.