An e-mail obtained by ABC 7 shows prison administrators were warned about a rope seen hanging from the prison more than one week before the escape.
The facility houses those facing federal serious federal charges while they await trial as well as convicts with court appearances in Chicago.
We have an inside look at the security that stands between those inmates and you.
"On a midnight shift you could have fewer than 20 officers guarding hundreds of people," said federal prison officer Herman Nelson. "Murderers, terrorists and gang members."
Mob boss Joe Lombardo. Terrorist David Coleman Headley. And Mexican drug cartel leader Zambada Nyebla.
Those are just a few of the more famous guests of the Metropolitan Correctional Center in the Loop.
In December, it became the scene of one of the most daring jail breaks in recent memory. Two inmates tied bed sheets together and shimmied down 17 stories to freedom.
"If you're not on top on top of your job, these kind of things will open," Nelson said.
Nelson spent 18 years working in federal prisons. He started as a guard and worked his way up to supervisor of investigations.
We showed him the internal email obtained by ABC 7 in which a prison officer told her supervisors about a possible escape plot.
She wrote: "I was informed by an inmate that there is a rope being dropped from the south side of the building between 1 and 3 a.m. The rope is supposed to be big enough to have something heavy on it."
The prison workers' union says she sent that email to her superiors 8 days before inmates Joseph "Jose" Banks and Kenneth Conley went out the window.
"Bar checks should have been done, people should have been interviewed, investigations should have been done," said Nelson. "From my sources I understand it wasn't done."
The guard's email continues: "I was advised to check the windows for cracks and openings from Unit 13 and up. You all can see what you come up with."
Staff say the MCC is chronically over-crowded and under-staffed.
The Bureau of Prisons reports it currently houses 692 inmates: 75 percent over capacity.
Nelson recalls a strikingly similar escape at this federal lock-up in downtown San Diego where he worked in the 80's. There, like here, permanent outside guard posts were reportedly non-existent.
"A prisoner sawed through the window, he climbed out on sheets and fell and broke his leg," he said. "A passerby - a citizen - saw him lying on the street and came in and got somebody and said you have a prisoner out on the street screaming for help."
A spokesperson for the Federal Bureau of Prisons declined to comment declined to comment Thursday.
A footnote: The warden of the federal prison in downtown Chicago at the time of the escape, Catherine Lineaweaver, has since received a promotion. She now runs the MCC in New York City.
