Federal officials are concerned about a large quantity of cell phones purchased in three different Missouri cities in less than a week.

According to the Columbia Police Department, a group of five or more men purchased the phones at about 9:30 p.m.at the Conley Road Walmart in Columbia. Investigators said they spoke to the men but didn’t have grounds to detain them.

“Right then and there I knew there was not something adding up about this. It’s not right, it doesn’t make any sense”, the witness told KQFX-TV.

“Somebody went in and bought 60 cell phones from Walmart that’s not normal for this area”.

Former Missouri Homeland Security Coordinator Paul Fennewald told ABC 17 the stores did the right thing by calling.

An unidentified witness was already taking Merritt’s advice to heart, when he reported a similar incident that happened just hours before at a Walmart in Columbia, Missouri, about 100 miles away.

Two men walked into the store in Lebanon over the weekend and bought 60 cell phones. They can be used to communicate in relative secrecy because they’re hard to trace if they are prepaid.

“That’s the first thing that ran through my mind that something bad could happen”, he said. The Washington Post reported authorities said they lacked evidence that the men meant to use the phones to commit criminal acts. He said everybody should do the same when they see something suspicious.

Law enforcement said cellphones are potential tools in the hands of terrorists.

WGEM News has reached out to Walmart’s corporate office to find out what its policies are regarding suspicious purchases, but the call had not been returned at the time of publication.