The acting US attorney general, Todd Blanche, on Sunday defended new criminal charges filed against former FBI head James Comey, insisting that the case was based on more than just an Instagram post from last year.

The Department of Justice announced a two-count felony indictment against Comey on Tuesday, charging him in connection with a picture he posted on Instagram last May.

The picture displayed seashells on the beach arranged in a formation to say “86 47”. 86 is shorthand for getting rid of something, and Trump allies accused Comey of threatening violence against the president.

Comey deleted the post, apologized, and said he didn’t know that’s what the expression meant and condemned violence. Comey has said he is innocent and denies any wrongdoing.

Trump has long seen Comey as a political enemy and frequently disparaged him on social media. Legal experts, including conservative allies, have met the new charges with skepticism, seeing it as a thinly-veiled effort to punish one of Trump’s political rivals (a previous criminal case against Comey in Virginia was dismissed last year).

Blanche, however, insisted on Sunday there was more to the case.

“Rest assured that it’s not just the Instagram post that leads somebody to get indicted,” Blanche said during an interview Sunday on NBC’s Meet the Press. “You prove intent with witnesses, you prove intent with documents, with materials.” Pressed by host Kristen Welker on what additional evidence there might be, Blanche declined to offer any.

“At the trial, a public trial, that will be open to the public, everybody in this country will know exactly what evidence the government has against Mr Comey,” he said.

Blanche is said to want to be permanently named attorney general and has moved aggressively ahead with cases targeting Trump’s political rivals in just the one month since he replaced Pam Bondi as the attorney general.

Thom Tillis, a Republican senator from North Carolina, said the justice department would need to offer evidence beyond the picture to prove it was a worthwhile case.

“If this whole case is based on a picture in the sand of a North Carolina beach, it again makes no sense to me,” he said during an interview on CNN’s State of the Union on Sunday. “It better be more than just the picture. There have to be facts and circumstances beyond that to convince me.”

Throughout the interview, Blanche also said career prosecutors and law enforcement officials had investigated the case. But experienced lawyers left the case earlier during the investigation, Bloomberg Law reported.

The prosecutor handling the case is a former New Jersey city councilman from New Jersey whose main prosecutorial experience has been in Medicaid fraud cases. W Ellis Boyle, the acting US attorney for the eastern district of North Carolina, which is overseeing the case, had not been a prosecutor before being tapped for his current job last year, according to Bloomberg Law.

Adam Schiff, a Democratic senator from California who has also been targeted by Trump, said on Sunday he had never seen such a weak case.

“I think this case is likely to be thrown out even before it goes to a jury,” he said on NBC’s Meet the Press. “It will absolutely be thrown out by a jury.”