An inmate wanted for murder in California escaped from the Cook County Jail complex Friday evening by using a fake gun carved out of soap-a ruse reminiscent of John Dillinger`s escape from jail in Crown Point, Ind., in 1934.

Robert Glotz, assistant director of the Cook County Department of Corrections, said the inmate used the fake gun to force a guard to disrobe. The inmate put on the guard`s uniform and walked out of the jail complex, Glotz said.

(History shows that the well-known story of Dillinger`s escape from Crown Point using a wooden gun was a hoax used to cover up the truth. Dillinger`s gun was real and had been smuggled to him in jail. Cook County authorities said the gun used in Friday`s escape truly was soap.)

Glotz said the soap gun was found later at 25th Street and California Avenue, about a block north of the jail complex located at 26th Street and California Avenue. The guard`s uniform was found on 25th Place, a few houses west of California Avenue.

Glotz identified the escapee only as Victor Thomas. Glotz said Thomas had been in County Jail since September, 1987, on three armed robbery charges. He said Thomas also was wanted on a warrant from Los Angeles.

A source in the Cook County sheriff`s office said the inmate`s real name was Vincent Chris Bruce, 26. The source said Bruce was wanted in California in connection with the slaying of three drug dealers.

Glotz said the inmate told jail officials Friday evening that he was ill. A guard took the inmate to Cermak Memorial Hospital, which is within the jail complex. The two buildings are connected by a tunnel.

In the basement of the hospital at about 5:50 p.m., the inmate pulled out his weapon made of soap and threatened the guard, Glotz said.

The inmate tied up the guard and then escaped with the guard`s uniform, badge, wallet and identification, Glotz said.

The source in the Sheriff`s Department said: ''This was a hand-carved, .25 caliber automatic, carved out of soap. The only part that wasn`t soap was the trigger guard. ''He even took the time to bore out the barrel and add a little blue tint to what appears to be black marker that he covered the soap with. And the gun even smells good.''

The inmate ''apparently got wind of the murder warrant lodged against him in California,'' the source said.

''Once in the tunnel where it is low lit,'' the inmate displayed his fake gun and then ''told the guard: `I am facing 25 to life. I`ll kill you in a minute,` '' the source said. The inmate then knocked the guard down and took his uniform.

''We really can`t fault the guard,'' the source said. ''With the low light in the tunnel, that piece of soap really looked real.''

Chicago police said the escape was discovered moments after the inmate walked out. The inmate then eluded guards during a foot chase in the neighborhood.

According to initial reports, the escaped inmate was supposed to be armed with a .357 Magnum taken from the guard. But the sheriff`s source said this proved false.

''The guard had an empty holster, and he forgot that he was not carrying a weapon when he was overpowered and beaten,'' the source said.

Correctional officers in the jail complex are allowed to carry guns to and from work, but not at work.

The source said the guard was a little foggy, apparently from being beaten, when he first described the circumstances to his superiors.