An FBI special agent hopes to send a rope that two bank robbers used to escape from a downtown Chicago lockup in 2012 to be displayed at the FBI Education Center in Washington.

The FBI and the Federal Bureau of Prisons haven't ever said whether any employees were disciplined after Joseph Banks and Kenneth Conley escaped from Chicago's Metropolitan Correctional Center in December 2012.

The pair smashed a hole in a cell window and climbed down 20 stories using a rope fashioned from bed sheets. Both men were recaptured within two weeks and are serving prison time.

Agent Timothy E. Bacha, who was assigned to the case, told the Chicago Sun-Times that he also wants to send to Washington concrete and a metal bar from the cell.

"We've learned from it, and hopefully it will never happen again," Bacha said. "But it wasn't your ordinary walk-away. It wasn't, you know, somebody helping — like some of the previous escapes you've had. These are two guys who defeated a wall."

Bacha doesn't have clearance to send all the materials but he hopes to soon. He has given other pieces of rope from the escape to the correctional center for training.

The men had enough rope to escape from even higher, Bacha said. He suspects the men hid the ropes inside their mattresses, which were missing foam when investigators checked the cell, Bacha said.