(CNN) -- New York Gov. Eliot Spitzer is under investigation for allegedly meeting with a prostitute in a Washington hotel, two sources with knowledge of the investigation told CNN.
Gov. Eliot Spitzer, with his wife, Silda, by his side, apologizes to his family and to the public.
One of the sources said Spitzer is identified in a criminal complaint as "Client-9," and that Spitzer's alleged involvement was caught on a federal wiretap.
The governor's statement came four days after federal prosecutors in New York announced charges against four people accused of running an international prostitution and money-laundering ring that catered to big spenders.
According to prosecutors, Emperors Club VIP charged between $1,000 and $5,500 an hour and operated in New York; Los Angeles, California; Miami, Florida; London, England; and Paris, France.
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Read the criminal complaint (PDF)The criminal complaint about the ring did not name any customers, but authorities intercepted text messages, e-mails and telephone calls.
On Monday, Spitzer apologized to his family and to the public for an undisclosed personal matter. "I have acted in a way that violates my obligations to my family, that violates my or any sense of right and wrong," he said, as his wife, Silda Wall Spitzer, stood by his side.
"I am disappointed that I failed to live up to the standard I expected of myself," he said. "I must now dedicate some time to regain the trust of my family."
Watch Spitzer's apology »Spitzer facts
Time magazine names Spitzer "Crusader of the Year" during his two terms as New York attorney general.
Tabloids label him "Eliot Ness," because of his reputation for rooting out corruption, busting white-collar criminals and tackling organized crime.
Spitzer is known for prosecuting several prostitution rings.
He attended Princeton and Harvard, then became an assistant district attorney in Manhattan.
He worked for three New York law firms and decided to run in his mid-30s for attorney general.
The first-term Democrat had been considered a rising star in his party.
Spitzer is married and has three daughters.
His statement came after a New York Times report based on a single unnamed administration official who said the governor had informed his staff he had been involved in a prostitution ring.
Spitzer did not address or deny the report, and he did not take questions.
Federal authorities are investigating allegations Spitzer met with a prostitute in a Washington hotel, a senior source with knowledge of the investigation told CNN.
Before the news conference, three Democratic sources -- one in New York's capital, Albany, one in New York, and one in Washington -- told CNN a top Spitzer aide had told them the governor would resign.
"The governor called his senior staff together and told them he wanted to inform them first about a major announcement of a personal nature," a prominent New York Democrat told CNN.
"To say this is a shock is an understatement," said CNN senior legal analyst Jeffrey Toobin, who went to law school with Spitzer.
Toobin called Spitzer, "the straightest arrow I know."
The Republican Governors Association has called on Spitzer to resign to "allow the people of New York to pursue honest leadership."
"The American people are tired of corrupt and hypocritical politicians. The governor of New York is just another in the long list of politicians that have failed their constituents," Nick Ayers, RGA executive director, said in a statement.
Spitzer's office, the U.S. Attorney's office in New York and New York Mayor Michael Bloomberg all declined to comment on Spitzer.
Spitzer, 48, served as New York's attorney general for eight years before being elected governor.
E-mail to a friendCNN's Kelli Arena and John King contributed to this report.
