Humphreys' device wasn't discovered until a cellphone carrier noticed regular interference in its towers along a 12-mile stretch of Interstate 4 around Tampa, FL. The company contacted the FCC to investigate, and it identified the vehicle with direction-finding equipment. According to Network World, when sheriffs pulled the Toyota over, their radios stopped working to contact the dispatcher, and they found the jammer under a cover in the backseat.
While it may seem relatively harmless, operating a cellphone jammer is quite illegal in the US. Humphreys is charged with allegedly operating the device and causing interference. However, the FCC only fined him for one violation each, totaling $48,000. The organization could have levied as much as $337,000 because he blocked signals for so long.