The acting district attorney of Nassau County described a state trooper’s allegations that Mr. Cuomo had run his hand across her stomach to be “credible, deeply troubling, but not criminal under New York law.”

Prosecutors in Albany would have had to clear a relatively high bar had they proceeded with the criminal charge, which required them to prove not only that Mr. Cuomo had touched Ms. Commisso, but that he did so with the intention of satisfying his own sexual desire, or to degrade her.

Because cases like these rarely have irrefutable physical evidence, much of the burden would likely have fallen on Ms. Commisso’s testimony. Of the roughly 1,400 cases like Mr. Cuomo’s brought in a typical year across the state, almost four in ten are dismissed or dropped, state criminal statistics show.

The case against Mr. Cuomo was riddled with controversy from the onset.

It began when Ms. Commisso filed a complaint with Sheriff Craig D. Apple of Albany County shortly after Letitia James, the attorney general, released her report on Aug. 3, which concluded that Mr. Cuomo had sexually harassed multiple women, including Ms. Commisso.

Sheriff Apple’s office investigated Ms. Commisso’s account and, nearly three months later, filed criminal charges against Mr. Cuomo in Albany City Court on Oct. 28, describing the case against him as “very solid.”

He did so, however, without consulting Ms. Commisso or coordinating with Mr. Soares’s office, which would be tasked with prosecuting the case.

The decision by Sheriff Apple was as unusual as it was unexpected, especially in a high-stakes case involving a former governor, and it was seen by some as a tactic to make headlines or pressure Mr. Soares, who was caught off guard, into pursuing the case.