(CBS/AP) CHICAGO - Police said two bank robbers remained at large Wednesday morning after pulling off a daring escape from downtown Chicago's high-rise jail on Tuesday. The pair escaped by scaling down 15 floors of the building using a makeshift rope fashioned from bed sheets hanging from the bars of a cell window.
Authorities are trying to figure out just when 37-year-old Joseph Banks and 38-year-old Kenneth Conley managed to flee the jail cell they shared. Both men were accounted for in a headcount around 10 p.m. Monday but they were reportedly missing during a 5 a.m. headcount Tuesday.
Investigators found a broken window and bars inside a mattress when they came upon the cell Tuesday morning, according to an FBI affidavit. Stuffed under blankets on two beds were clothing and sheets, shaped to resemble a body.
Hours after the escape, the rope of bed sheets could be seen dangling down the side of the Metropolitan Correctional Center. At least 200 feet long and knotted about every 6 feet, the rope was hanging from a window that was 6 feet tall but only 6 inches in diameter.
Authorities said Banks and Conley were the first inmates to escape from the federal facility in nearly two decades.
The meticulously planned escape happened just a week after Banks made a courtroom vow of retribution. The men, who have yet to be sentenced, are facing hefty prison terms, and the FBI said they should be considered armed and dangerous.
The 27-story facility is one of the only skyscraper lockups in the world, and experts say its triangular shape was meant to make it easier to guard, theoretically reducing blind spots for guards. The only other escape from the nearly 40-year-old facility occurred in the mid-1980s, U.S. Marshals Service spokeswoman Belkis Cantor said.
The FBI believes both men were in Tinley Park, a heavily wooded area about 25 miles south of Chicago. Authorities were scouring a local forest preserve in the afternoon. SWAT teams stormed at least one home in Tinley Park, but neither man was found. Evidence suggested that both had been at the home just hours earlier, according to the FBI.
Banks, known as the Second-Hand Bandit because he wore used clothes during his heists, was convicted last week of robbing two banks and attempting to rob two others. Authorities say he stole almost $600,000, and that most of that still is missing.
He was restrained during trial because he threatened to walk out of the courtroom. He acted as his own attorney and verbally sparred with the prosecutor, at times arguing that U.S. law didn't apply to him because he was a sovereign citizen of a group that was above state and federal law.
After he was convicted by U.S. District Judge Rebecca Pallmeyer, he said he would "be seeking retribution as well as damages," the Chicago Sun-Times and Chicago Tribune reported.
When the judge asked how long he needed to submit a filing, Banks replied: "No motion will be filed, but you'll hear from me."
Conley pleaded guilty last October to robbing a Homewood Bank last year of nearly $4,000. Conley, who worked at a suburban strip club at the time, wore a coat and tie when he robbed the bank, and had a gun stuffed in his waistband.
Both men were being held in the Chicago lockup, which houses around 700 inmates awaiting trial in the Dirksen Federal Building a few blocks away.
Architect Harry Weese designed the building in the mid-1970s shortly after notorious prison riots in Attica, N.Y., and was asked to design a "more humane" lockup, said Jennifer Lucente of Chicago Architecture Foundation.
That was one reason Weese ensured each cell had a window, she said.
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