Developed by Sandia National Laboratories and field-tested by the South Texas Specialized Crimes and Narcotics Task Force, the commercial detector collects samples by drawing in vapor from the air space close to the suspicious object or area. An operator may also swipe a suspicious area to collect a sample. The task force has field-tested the unit in a busy area along Texas highway 77, where the Hound system has played a key role in resolving a variety of incidents. This has included identifying liquid and crystal methamphetamine after a routine traffic stop by local law enforcement. The Hound system was also used to investigate the content of a tanker truck that had arrived at a military base without the proper inspection seals on its cargo; no chemical or explosive substances were detected, and the delivery was allowed to proceed. In another case, the Hound system located traces of gunpowder on a decomposing corpse. In its field testing the Hound system is used only when there is probable cause to believe that a dangerous or illegal substance is being concealed.