Resigning won't spare Eliot Spitzer from the heat of a criminal investigation — federal prosecutors must still decide what to do with the case of the disgraced New York governor and the prostitutes.

A law enforcement official said Spitzer's high-powered defense team was believed to be negotiating a plea deal with prosecutors over his connection to a high-end prostitution ring, but attorneys would not comment Thursday about the discussions.

"Corruption cases often pose a dilemma for the prosecutor," said Evan Barr, a private practice lawyer who once handled such cases for the same Manhattan U.S. Attorney's Office that is now weighing how to proceed with Spitzer.

"If you charge a public figure under an obscure or rarely used legal theory, the critics will say the prosecution is politically motivated; if you decline to charge under the same circumstances, the critics will say the prosecutor is going easy on the would-be defendant because he or she is a prominent person," Barr said.