CHICAGO – Two convicted bank robbers were on the run after using a knotted rope or bed sheets to escape from a high-rise federal jail in downtown Chicago early Tuesday, a week after one of them made a courtroom vow of retribution.

The two men were first unaccounted for during a 5 a.m. head count, but it’s unclear if they were still inside the 27-story Metropolitan Correctional Center at the time, U.S. Marshal’s Service spokeswoman Belkis Cantor said.

Local shop owners said police didn’t swarm the area until more than three hours later, when what appeared to be a rope, knotted at six-foot intervals, could be seen dangling from a window about 20 stories up.