here is allison harris with fox 4 dallas/fort worth. all of it began 45 minutes ago at dallas police headquarters. >> we did not hear anything or see anything that alerted our attention until we heard that suv pull in and officers started to run in. it was a shock to the media who were looking down the street where all of the police presence is. we did not know that anything caused them to, you know, to move in. we did not hear anything at all. it was calm and quiet until officers started to move in. we are not exactly sure w happening. >> allison harris from fox 4 dallas. this mystery report has police officers very concerned. they blocked off the street. we understand that they are sweeping their own parking garage. the garage they use to park when they come to work. the gunman, micah johnson, was using a parking garage as his sniper's perch only adds to the tension that you know they are feeling. all of this is not even 48 hours old when they were helping their fellow citizens at a rally protesting police when all of a sudden 12 poli