Federal investigators are searching for 19 guns that remain missing after being reportedly snatched from their UPS packaging in Minneapolis.

According to Minneapolis police, a UPS employee at its northeast distribution center was observed concealing something in his pants and under his shirt at the end of his shift. 

The police report then details the worker swiped the firearms from boxes that were meant to be loaded onto UPS trucks. At least 27 handguns were reportedly stolen.  

On Monday, police confirmed one person is in custody and was arrested at Mystic Lake Casino, where detectives also found drugs and thousands of dollars in cash. Eight of the weapons have also been recovered, police said.

"At UPS, we have zero tolerance for theft and take action when it occurs," a UPS spokesperson told WCCO. "We are fully cooperating with law enforcement in their investigation and referring any additional questions to them."

The company's website lists several protocols for shipping firearms, including packaging them separately from ammunition. The boxes also cannot contain any markings that might imply something related to firearms is inside.

The Hennepin County Attorney's Office on Monday said it received the case, but a spokesman there said there's "insufficient evidence at this time" to file charges, and that the investigation is ongoing.