Authorities say 2 inmates escape from federal prison in downtown Chicago CHICAGO - Two convicted bank robbers were on the run after using a knotted rope or bed sheets to escape from a federal prison window high above downtown Chicago early Tuesday, a week after one of them made a courtroom vow of retribution. The escape occurred sometime between 5 a.m. and 8:45 a.m. when the inmates were discovered missing, Chicago Police Sgt. Mark Lazarro said. Hours later, what appeared to be a rope, knotted at six-foot intervals, could be seen dangling from a window of the Metropolitan Correctional Center approximately 20 stories above the ground. Joseph "Jose" Banks, 37, and Kenneth Conley, 38, had been wearing prison-issue orange jumpsuits, but now might be wearing white t-shirts, gray sweat pants and white gym shoes, Lazarro said. The FBI said the men were last seen together in the Tinley Park area, about 25 miles southwest of Chicago, and that they should be considered armed and dangerous. SWAT teams stormed a Tinley Park home early Tuesday afternoon, but the escapees were not there, FBI Special Agent Frank Bochte said. He said there was evidence the two had been there earlier, and authorities were using dogs and helicopters to search various places in the Chicago area where the two had connections. Banks is described as a black man, 5-feet-8, weighing 160 pounds. Conley is described as white, 6 feet tall, weighing 185 pounds. The men apparently descended from a thin window barely half a foot wide on the flat south side of the prison into the alley below. The wall faces a parking garage and is above air conditioning or heating units. Crowds of people gathered outside the building where the ropes still blew in the breeze, shaking their heads in disbelief that someone could have escaped from a lockup in the heart of downtown Chicago, just a block or two from key federal court and office buildings. The owners of several small shops across the street from the wall said they didn't see any police activity until around 8:30 a.m., when a dozen or more police cars and SWAT teams rushed into the area. Some police officers sprinted for a nearby subway entrance. It was clearly already too late. They were long gone," said Randy Cohen, owner of the Royal Jewelry and Loans store 10 or 20 yards from where the inmates scaled down the rope. Homeland Security and U.S. Marshal's Service agents questioned him later in the morning and asked if security cameras on his building could have captured the escape or the men fleeing, Cohen said. He said he didn't think the cameras would have been pointed in the right direction. Liquor store owner Baljit Singh has a clear view of the side of the prison where the men escaped. She said there was no indication anything was amiss when she arrived at work at 7 a.m. The facility, which houses around 700 inmates, is one of the only skyscraper prisons in the world, said Jennifer Lucente of Chicago Architecture Foundation. Architect Harry Weese designed the building in the mid-1970s. Its triangular shape is supposed to reduce the number of blind spots for guards, Lucente said. Each cell has a window as part of the building's humane design, she said. Security concerns have arisen before about the lockup. Last year, federal authorities opposed a request from attorneys for Mexican drug-cartel lieutenant Vincente Zambada -- held there on trafficking charges -- to let him out on the rooftop recreational area, where in the summer inmates can be seen playing basketball. Officials feared snipers could target Zambada or that he might try a daring escape from atop the 27-story building. He was later moved to a lockup in Michigan. In 2010, the brother of Hollywood director Christopher Nolan was sentenced to 14 months for plotting to escape from the facility by hiding a rope made out of bed sheets in his cell. Matthew Nolan, who was being held pending an extradition request, pleaded guilty to possessing contraband in jail and obstruction of justice. 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 more. Authorities say he stole almost $600,000 and that most of that is still missing. After U.S. District Judge Rebecca Pallmeyer convicted him, 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 of nearly $4,000.