'On the hunt': Legal experts explain how prosecutors are zeroing on Trump in tax fraud scheme
Donald Trump, Jr., Melania Trump, Donald Trump, Ivanka Trump and Eric Trump

The Trump Organization isn't a complicated setup, and investigators seem to have its leader targeted for prosecution.

The company and its chief financial officer Allen Weisselberg were indicted July 1 for tax fraud, but former president Donald Trump was not personally charged despite having almost unlimited authority over his family business, reported the Huffington Post.

"The Trump Organization is an avatar for Donald Trump, in every way imaginable: financially, emotionally and psychologically," said Trump biographer Tim O'Brien. "The core company is a mom-and-pop shop on Fifth Avenue."

O'Brien can't imagine that Trump didn't know about the scheme described by prosecutors, but to indict the ex-president they must show that he knew the employee fringe benefits were illegal but approved them anyway.

"There has to be personal, specific knowledge," said Danya Perry, a former federal prosecutor in New York City. "You can't just impute knowledge."

Trump formed hundreds of interlocking corporations for his various assets, which O'Brien says was an overreaction to his near bankruptcy in the 1990s, but the journalist said all roads in the Trump Organization come back to its namesake.

"This is basically a corner grocery with a guy behind the counter munching on a hamburger," O'Brien said,"and he's the owner of the store."

His longtime personal attorney Michael Cohen, who served a prison term for crimes committed on behalf of his former boss, said there's no way Trump didn't know about the tax fraud scheme.

"The checks for bonuses were all signed by Trump," Cohen said. "The argument that he was unaware of these funds being given to Weisselberg or others is pure nonsense."

Trump offered a hint about his defense when he told supporters at a Florida rally that he didn't know fringe benefits should have been reported for tax purposes, but Perry said that may offer useful clues to prosecutors.

"It certainly could be seen an admission," Perry said. "I'm sure the prosecutors are watching him very closely."

Blaming everything on Weisselberg might not work, according to ethics lawyer Norm Eisen, who served in Barack Obama's White House and worked on the House committee leading Trump's first impeachment.

"It would be beyond implausible -- it would be ridiculous," Eisen said. "Prosecutors have built the framework for a future case targeting Trump personally. ... Prosecutors are on the hunt."