First, he located the recordings for the parabolic microphones and opened them up. He played one of the files and listened for a moment, adjusting the volume of the computer’s speakers.

“What are you trying to find?” Carter asked.

“It would take forever to listen to all of those for one specific sound,” Nic added.

Burke shook his head and sighed. “Duh, wave forms and timestamps. I’m just checking the audio quality of the speakers. Let me work.”

He found a program on the system for audio manipulation. It wasn’t the ideal application, but it should serve his purposes. Dropping the wav files into the program, he used shortcut keys and clicked his way around until he had cut out the time frame from each file corresponding to fifteen minutes before the SWAT team breached and thirty minutes after. Then he zoomed in on each wave form, looking for the peaks. Ignoring the sounds from the actual breach and the commotion that followed, he checked for smaller disturbances that the powerful microphones may have registered. The first two files had nothing, probably pointed in the wrong direction. The third one registered what could have been the proper vibration, but it was too indistinct. But on the fourth file, he hit pay dirt.

Isolating the few seconds of audio, he cranked the speakers and pressed the play button.

The three of them listened, and there it was. Burke smiled and played it again to be sure. He heard the small thwump and rattle and then a sound like static, all very quiet, recorded as part of the ambient noise in the far distance.

“Okay, microphone number 4. Where was that one positioned?”

Nic didn’t answer. Burke swiveled his chair around and snapped his fingers at the confused-looking SWAT officer. “Work with me here, people.”

“Uh, let me check.” He walked into another room and grabbed a map describing the placements of emergency response teams, snipers, and microphones.

“That one was on the South side of the building, pointed at the front windows,” he said.

“Okay, great,” Burke said as he brought up an internet browser and an aerial view of the property and the shopping center. The origin point of the sound had to have been behind the building. He scrolled up to find a large open field of grass there, probably a spot being prepared for further expansion of the strip mall. But behind that was a tiny subdivision of older homes. Burke could only see the terra-cotta tiles of their roofs from the overhead view. In his mind, he visualized a three-dimensional image of the front of the building. Then he imagined the view of the building from behind the microphone. Playing the wav file again, he listened for the direction of the sound and factored that with the data from the aerial view.

He had an approximate location, but they would need to investigate further on the ground.

Pushing the chair back and bumping into Nic, Burke headed toward the comm center’s exit. Carter grabbed his arm, and Burke reflexively slapped it away.