The 10 inmates who broke out of a New Orleans jail in a stunning overnight escape last week used electric hair trimmers with multiple clipper blades to help cut their way through the cell walls, a source with direct knowledge of the investigation told CNN.

Three Orleans Parish jail inmates staged an unsuccessful escape attempt through the ceiling of pod 1D roughly two weeks before the 10-person jailbreak via its toilet on May 16, court records show.

The escape spread anxiety through one of America’s most beloved tourist cities, opening new wounds for victims’ relatives and forcing some into hiding.