CHICAGO - A federal judge ruled Thursday that the Cook County Jail's policy of giving male inmates one last strip search before releasing them from custody violated their constitutional rights.

The practice violates both the Fourth Amendment guarantee against unreasonable searches and the Fourteenth Amendment's assurance of equal protection under the law, said U.S. District Judge Elaine E. Bucklo.

She ruled in a four-year-old suit filed by Quentin Bullock and Jack Reid, two former inmates who were acquitted of charges in court but still strip searched before being released from the jail.

The sheriff's office, which oversees the jail, fought the lawsuit, saying a final strip search was necessary for security.

"We don't agree with it (the ruling) and we will seek a court review," said Penny Mateck, a spokeswoman for Sheriff Tom Dart.

Jail officials say inmates who have been acquitted by a court cannot simply be released. They have to be returned to the jail where officials run a check to determine if there are other, unrelated charges outstanding that might keep them behind bars.

Such prisoners might smuggle weapons or other contraband back into the jail and leave it with other inmates, officials say.

But the jail has long followed a practice of not strip searching female inmates who return before discharge. They are kept in a separate holding area while officials run checks to see if they are ready for release.

"Defendants argue that they have no animus toward male discharges, that their motivation is simply to preclude weapons and contraband from being smuggled into the jail," Bucklo wrote in her 23-page decision.

"As already set forth and admitted by defendants, however, female discharges are also capable of smuggling contraband into the jail," she said. "This salient fact fatally undermines defendants' argument."

Four bullpens capable of holding 120 inmates each during the wait to be discharged would cost $50,000 to $200,000 to build, Bucklo said.

It was the latest blow to what officials call the nation's largest county jail located on a single site.

A 17-month federal investigation made public July 17 said serious sanitation and medical care problems exist in the jail, as well as violence directed against prisoners who clashed with guards or failed to follow commands.