A federal review cites poor judgment by a security guard who found a bag outside a government building in Detroit last year and stashed it under a desk where it remained for weeks – with neither the guard no anyone else in the building aware that it contained a bomb, according to an article from CNN.

The canvas bag, containing a small locked Sentry safe, was discovered February 26, 2011, outside the 27-story building that houses the FBI and other offices, and it remained at the guard desk until it was identified as a threat three weeks later, the article says.

During that time, at least two employees X-rayed it in an unsuccessful attempt to determine its contents. One guard shook it in another failed attempt to discover more about it, and a federal inspector conducted four routine checks of the guard post without discovering that the bag contained an explosive device, according to a report by the inspector general – an independent watchdog.

The inspection found that the contractor, DECO Inc., “committed multiple breaches of its contract” with the Federal Protective Service (FPS), but that the shortcomings regarding the bomb “were the result of poor judgment by the guard, not systematic problems with DECO,” the CNN article says.

Company officials had reason to believe that the guard, who was not identified, “should have known how to respond to the bag,” the report says.

The guard was a sergeant with the Detroit Police Department and had received refresher training just three months before the incident. One FPS official said that he was one of the best guards in the building, the CNN article reports.

On the day of the incident, however, the guard “misidentified the bag as found property and never treated it as suspicious, despite not knowing its contents,” the report says.

The bag was placed under the security desk in the McNamara building, where other guards did not regard it as suspicious because the space was used to store found property and personal belongings, the article says.

An FPS inspector did not identify the explosive during four inspections, noting that the post was “clean and orderly” and “free of unauthorized items,” CNN says.

On March 18, 2011 – 21 days after the bag’s discovery – two guards grew suspicious and screened it, informing an FPS inspector when they could not identify its contents. At that point, the inspector determined the bag possibly contained an explosive and took action, the report says.

The Detroit Police Department harmlessly detonated the improvised explosive device.

The guard in question, as well as a guard and a supervisor who X-rayed the bag and incorrectly identified its contents were fired by DECO, and a second supervisor resigned before being fired, CNN reports.