**** UPDATE ****
It has been confirmed that there is one person armed with a gun inside Walmart and at least one hostage.
We do consider this a work-place violence situation at this point.
...All agencies are on scene, including Amarillo SWAT, APD, AFD, RCSO, PCSO and DPS. The SWAT robot is currently being utilized.
Although there were reports of shots fired when officers arrived on scene, there have been no confirmed injuries.