NEW YORK - Federal prosecutors announced Thursday that they will not bring criminal charges against Eliot Spitzer for having sex with prostitutes, removing a legal cloud that has surrounded the former governor since his epic downfall eight months ago.

Manhattan U.S. Attorney Michael Garcia said that investigators found no evidence that Spitzer misused public or campaign funds for prostitution, meaning prosecutors had very little ammunition in bringing a case. The federal government typically does not prosecute clients of prostitution rings.

“After a thorough investigation, this office has uncovered no evidence of misuse of public or campaign funds,” Garcia said. “We have concluded that the public interest would not be further advanced by filing criminal charges in this matter.”

The announcement by Garcia signaled the end of the bombshell investigation of Emperors Club VIP, and meant that nine other men described in an indictment as clients of the lucrative prostitution service also have escaped charges. Those clients were never identified.

Legal experts said local authorities technically could still charge Spitzer as a john, but that would be highly unlikely.

A remorseful Spitzer issued a statement in which he expressed relief that he will not face charges.

“I appreciate the impartiality and thoroughness of the investigation by the U.S. Attorney's Office, and I acknowledge and accept responsibility for the conduct it disclosed. I resigned my position as Governor because I recognized that conduct was unworthy of an elected official. I once again apologize for my actions,” Spitzer said.

Spitzer was out of town and unavailable for further comment.

Spitzer resigned March 12 after it was disclosed he was referred to in court papers as “Client-9,” a man who met a prostitute in a Washington, D.C., hotel. Garcia said that Spitzer later revealed to investigators that on multiple occasions he arranged for women to travel from one state to another state to engage in prostitution.

The scandal ruined a promising political career for Spitzer, who won a landslide election in 2006 with a vow to clean up corruption. He has remained out of the spotlight since his resignation, spending time with his wife and three daughters, working for his father's real estate business and occasionally being photographed running in Central Park.

He also assembled a high-powered team of lawyers who made an intense behind-the-scenes lobbying effort with the U.S. Attorney's public corruption unit. His legal team included former prosecutors.

Prosecutors' options were limited once they found he didn't violate campaign finance rules.

Authorities could have charged Spitzer with violating the Mann Act, a federal law that bans carrying women or girls across state lines for “prostitution or debauchery, or for any other immoral purpose.” But the legal experts say the law is rarely used to prosecute johns.

“I would have been more surprised had he been charged,” said Elkan Abramowitz, chief of the criminal division in the U.S. Attorney's Office in Manhattan in the 1970s. “Once they determined that he didn't use state or campaign money but apparently must have only used his personal money, I am not surprised they decided not to prosecute.”

Another former federal prosecutor, Brad Simon, said the decision may have been influenced by other factors, such as the lobbying effort by Spitzer's attorneys.

Prosecutors “have discretion and they used it,” Simon said.

The lawyer for the former call-girl whose tryst with Spitzer sparked the investigation, Ashley Alexandra Dupre, said “Ashley is pleased that this matter is behind her.”

“She's going to move on with her life,” attorney Don D. Buchwald said.

Four people pleaded guilty in recent months to running the prostitution operation.

Michael C. Farkas, the lawyer one of the escort service's booking agents, blasted the decision. His client, 36-year-old Tanya Hollander, pleaded guilty and admitted to helping run the ring, and is scheduled to be sentenced later this month.

“She still faces a jail sentence, while some other more infamous actors in this matter do not. It would be a sad injustice if that were to occur,” Farkas said.

Murray Richman, lawyer for the 62-year-old operator of the escort service, Mark Brener, said prosecutors “did the proper thing.” He said he could not “perceive how Spitzer was involved in any criminal conduct,” though the governor paid a price for his moral choices.

He said the lesson of the case “is that if you're a public official, you can't be a private person.”