The sweeping tax-fraud indictment unsealed on Thursday against Donald Trump's longtime accountant Allen Weisselberg threatens the 73-year-old executive with years in prison and puts heavy pressure on him to implicate the former U.S. president.

Prosecutors allege that Weisselberg, the Trump Organization's chief financial officer, evaded more than $900,000 in taxes by taking part of his annual pay in benefits including apartments, luxury cars and a cash bonus at the holidays, described in financial records as "holiday entertainment."

Judges are often reluctant to sentence elderly defendants with no prior record to prison time, said Ethan Greenberg, a retired New York judge who is now a defense lawyer. But the indictment — detailing a deliberate scheme to avoid taxes on $1.7 million in income over 16 years — "convinces me, and should convince Weisselberg, that a substantial prison sentence is possible," Greenberg said.