KANSAS CITY, Mo. — In less than a week, law enforcement agencies in three different Missouri cities have investigated the purchase of large quantities of cell phones at Walmart stores. In two cases, the Federal Bureau of Investigation was contacted.

Last Saturday, KSPR reports that police were called to a Lebanon, Mo., Walmart when two men purchased about 60 cell phones early in the morning. Police tell KSPR that terrorists can use cell phones as bomb detonators in addition to using them for communication, and can be hard to track if prepaid.

KSPR says the men weren’t arrested because police say they hadn’t technically done anything wrong. However, the Laclede County Sheriff’s Office says it contacted the FBI.

An FBI spokesperson told FOX 4 on Wednesday that it’s standard procedure for law enforcement agencies to contact them if they deem something to be suspicious.

On Monday, KMIZ reports that Columbia police say they were alerted to something similar when several men bought dozens of phones at a Walmart late last week, and paid in cash.

“It’s not right, it doesn’t make any sense,” a witness told KMIZ. “Who’s going to order 50 phones for Christmas? Who does that?”

On Wednesday, the Macon County Sheriff’s Office said it is investigating a similar report at a Macon Walmart:

A former coordinator for the Office of Homeland Security in Missouri, Paul Fennewald, told KMIZ that calls to police were warranted in these cases.

“That’s the first thing that ran through my mind that something bad could happen. If I had seen the same thing, I probably would have called somebody also,” he said.

The FBI spokesperson also told FOX 4 that just because they were contacted about a case doesn’t necessarily mean that the FBI is also investigating, and that the calls could come in out of an abundance of caution.