Mr Barr’s comments came on the day that current AG Merrick Garland installed a special counsel to oversee investigations into the one-term president.
The Republican was asked in a PBS interview about the legal danger facing Mr Trump over the probe into top secret documents the FBI found hidden at Mar-a-Lago.
“If the Department of Justice can show that these were very sensitive documents, which I think they probably were and also show that the president consciously was involved in misleading the department, deceiving the government and playing games after he had received the subpoena for the documents, those are serious charges,” said Mr Barr.
“I personally think that they probably have the basis for legitimately indicting the president. I don’t know, I’m speculating. But given what’s gone on I think they probably have the evidence that would check the box.”
Mr Barr added that it was important for the Justice Department to prosecute anyone, including a former president, if they had broken the law, but that it also had to be weighed up against the damage done to the office.
Earlier in the day, Mr Trump reacted angrily to the appointment of the special counsel Jack Smith and bizarrely insisted he would not “partake in it.”
“I have been going through this for six years — for six years I have been going through this, and I am not going to go through it anymore,” Mr Trump told Fox News Digital on Friday after the counsel was revealed. “And I hope the Republicans have the courage to fight this.”
“I have been proven innocent for six years on everything — from fake impeachments to [former special counsel Robert] Mueller who found no collusion, and now I have to do it more?” he added. “It is not acceptable. It is so unfair. It is so political.”