(WBIR) Knoxville police say a hand grenade found outside the Walmart on Clinton Highway Monday morning was an "outdated" device that could have come from the Wold War II era.

A mowing crew discovered the grenade in the grass near the tire and lube center and called police at about 9 a.m.

Darrell DeBusk, with the Knoxville Police Department, said the grenade initially appeared to be live. It contained an unknown substance, but experts weren't able to determine if it was inert.

An explosive team transported the device to a remote location to deactivate it.

Investigators don't know how long the device was on the property before it was discovered