Anne Arundel County police said yesterday that an allegedly retarded man whose true identity they had spent much of the summer trying to establish is a fraud who has attempted similar hoaxes in at least three other states.

A police spokesman said that Leonard J. Spreigl, 24, a native of Minnesota, is being sought on a charge of giving false information. Since he was found outside a restaurant in Glen Burnie on July 8, Spreigl had told police his name was "Jimmy Connors" and that he had been abandoned by his parents, whom he could not identify. Doctors who subsequently examined him said he was retarded, and a widely publicized search was conducted to locate his home.

According to police, Spreigl admitted his true identity this week while undergoing psychiatric testing in Baltimore. The testing had revealed that he was of normal intelligence.

Social workers then contacted his foster parents in Minnesota who confirmed Spreigl's story and said he had attempted the same hoax in Texas, California and Hawaii.

Speigl was then sent to the Helping Up Mission, a shelter for the poor in Baltimore. He walked away from the home on Tuesday and has not been seen since.

Sgt. Richard E. Davis said police are certain the latest version of Spreigl's past, provided by social workers, is the correct one. "Through the phone conversation with Minnesota, they learned that he's done this sort of thing in the past, in several states," he said.

Police knew Spreigl had been in California when the FBI matched his fingerprints with those of a man taken in by San Diego sheriffs in 1977. California records showed Speigl, then calling himself Ronald T. Middleton, was found under similar circumstances in San Diego. He told San Diego authorities he left his home in Texas when his father died.

When Spreigl was found outside a Burger King in Glen Burnie in July, he told police his parents had abandoned him. He was put in Crownsville Hospital Center, a mental institution in Anne Arundel County, where psychiatrists said he was mentally retarded.

Dr. Jerry Kowalewski, of the Crownsville Hospital, said yesterday that the hospital could not release any information about Spreigle.

Crownsville is not permitted to keep retarded patients, and Spreigl was later sent to a home for the retarded. He was briefly returned to Crownsville after he injured a hand and gave himself black eyes by beating himself against a wall. He subsequently went back to the home.

Police and social workers helping Speigl believed his story, and the case attracted considerable publicity. In July, police distributed photographs of "Jimmy Connors" and composites of the man he said was his father. Deans and a social worker drove him around the Washington area, where Speigl said he lived, searching for his home. "We have nothing to suggest that Jimmy isn't telling the truth," Deans said in July.

John Coffin, the lawyer appointed to handle Spreigl's legal situation, said at the time, "When you listen to him, his story is really based on what he knows. If you try to add something, he'll object. It seems rather plausible. It just dosn't add up to making him bogus."

Davis said the police officers who had worked for months on the case were extremely upset. "A lot of work has gone down the drain from July," he said. "I think Det. Deans expressed it very capably: Sometimes you investigate a case with your heart. This was one of those cases."