An Upper Marlboro man who was jailed in the Prince George's County for 10 days even though he was innocent of any wrongdoing was apparently the victim of a stolen identity scam perpetrated by a member of his family, authorities said yesterday.

Curtis Jeffery Williams, 21, was arrested in Forestville on Aug. 6 by Prince George's police after officers discovered during a routine check that Orlando police had obtained a fugitive warrant for him. Although Williams protested that he was innocent and said there must have been some mix-up, he was jailed as authorities began proceedings to extradite him to Florida.

Williams spent 10 days in jail without bond until Prince George's officials determined that he was telling the truth: that he was not the man wanted on drug charges in Orlando and that he was a victim of mistaken identity. He was released from jail Monday.

"I'm mad that it took them that long to figure it out," Williams said yesterday. "If my mother hadn't called so many people and if I didn't have money for a lawyer, I'd still be in jail right now. Nobody cared."

Sgt. Bill Ament, a spokesman for the Prince George's sheriff's department, called the incident unfortunate, but he said deputies moved as quickly as possible to straighten things out when it became apparent they had the wrong man.

Ament said the sheriff's department received a warrant for Williams's arrest July 15 from the Orange County Sheriff's Department in Orlando, which reported that Williams was a fugitive wanted on charges of marijuana possession and resisting arrest. The warrant listed Williams's name, birth date and an old home address in Forestville.

But Florida authorities were really looking for a relative of Williams--a relative who passed himself off as Williams when he was arrested in Orlando in April, according to Williams's family. The relative is not in custody.

Ament said it took several days to sort out the case because Orlando officials were slow to send the fingerprints and photograph of the man they were after. Once it became clear that the fingerprints didn't match, he said, Williams was released.

He said such mistaken-identity cases are highly unusual. "It's not unheard-of, but in those rare cases in which it does occur, there is usually some kind of connection" between the innocent person and the real suspect, he said.

Anthony Martin, a Greenbelt lawyer who represents Williams, said the sheriff's department and other court officials took too long to admit they had made a mistake.

"I'm not saying the people up here acted in bad faith," he said. "But the government should have figured out fairly early on that they had the wrong guy."

CAPTION: Curtis Jeffery Williams, shown with his mother, Cheryl Williams, was jailed in Prince George's County in a case of mistaken identity.