MEMPHIS (AP) — Most of the roughly 400 guns that were stolen from a United Parcel Service facility in Tennessee have been recovered in the Chicago area, federal authorities say.

Authorities seized about 365 Ruger .22-caliber and .380-caliber firearms after police officers responded to a call about suspicious activity in the southern Chicago suburb of Midlothian on Sunday afternoon — about 12 hours after the guns were taken from a UPS facility in Memphis, a Bureau of Alcohol, Tobacco, Firearms and Explosives agent said in court documents Tuesday.

ATF had said the guns being shipped from a Ruger factory in North Carolina were taken by two men in a U-Haul truck. ATF spokesman Michael Knight said the truck was recovered along with the guns.

Court documents said officers found the truck at a store parking lot in Midlothian and questioned 24-year-old Roland Jackson of Chicago and 18-year-old Taveyan Turnbo before they both ran away.

Turnbo was arrested hours later and faces federal charges of possessing stolen firearms. Court documents said he denied taking part in the theft at the UPS facility.

Jackson faces federal charges of being a convicted felon illegally possessing firearms. The ATF said he remained at large Tuesday.

The estimate of 400 stolen firearms makes it one of the largest single gun thefts the ATF has investigated, Knight said.

Turnbo told investigators he and Jackson had sold at least three of the guns for a total of $400, according to court documents.

UPS said it is cooperating with law enforcement.

ATF had asked the public to send social media posts, photos or any other information related to the theft. A $5,000 reward was offered for information leading to an arrest and conviction in the case.