Think this answers your question:

“ Mr. Bragg’s office must meet a higher bar to bring a criminal case and has encountered a number of challenges in pursuing Mr. Trump, including its inability thus far to persuade any Trump Organization executives to cooperate.”

Very puzzling

It sounds to me like Alvin Bragg, the elected NY County DA is ambitious (corrupt NYC politician) and they've got something damaging on him. He is going to drop the case and hence the resignations. Pretty fucked up but it's so obvious. He got elected promising one thing, then pulled a Mitt Romney style Etch-a-Sketch moment once in office. Dangerous man. [ny1.com]