JANESVILLE, Wis. (WTVO) — Police in Janesville have yet to identify the person responsible for including a live explosive device in their donation to a local Goodwill outlet.

Police were called to the Goodwill Store and Donation Center in Janesville on Friday at 11 a.m., after employees discovered ammunition and a “military grade” explosive device while organizing donated items, according to an alert issued by police.

Amid the investigation, officials evacuated nearby businesses while residents were urged to avoid the entire city block.

Bomb squad technicians with the Dane County Sheriff’s Office ultimately identified the device as “a live cluster bomblet,” police said.

“The device was collected by the Dane County Sheriff’s Office Bomb Squad and will be destroyed,” Janesville police wrote in an update Friday afternoon.

The evacuated area, as well as the Goodwill, were reopened to workers and residents the same day.

The person responsible for placing the device within the donated items had yet to be identified as of Monday afternoon, the Janesville Police Department confirmed to Nexstar.

Speaking with Nexstar’s WTVO last week, Sgt. Benjamin Thompson of the Janesville police further indicated that the ammunition and device were “accidentally” included among a donation, rather than intentionally placed there.

Janesville police thanked residents and workers for their responsiveness during the investigation.

“The safe evacuation of the impacted businesses to ensure a safe resolution could not have been made possible without the cooperation and patience of those impacted,” the department wrote.