AUSTIN, Texas — One year ago, police were asking for the public's vigilance after packages exploded at Austin homes, claiming two lives.

• APD flooded with calls about packages
• Police used NanoXray machines
• Bomb squad goes through many hours of training

Hundreds of calls flooded the police department as officials warned residents not to touch any packages they weren't expecting. While investigators with the Austin Police Department Bomb Squad worked to get clues after the first explosion, a second blast rocked the city, followed by a third, then a fourth. A total of seven bombs, including the one self-detonated by the suspect, launched the city into fear.

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Thousands of phone calls to APD about suspicious packages put immense pressure on the bomb squad, made up of about a dozen people.

Law enforcement agencies from across the area arrived to help. They used devices like NanoXray machines that helped investigators approach certain packages to give them a better idea of what was inside. Learning how to operate these devices, along with how to identify threats is all part of the job for bomb technicians.

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“X-ray is the name of the class from the bomb school,” said Austin Police Officer Jeff Joseph. “It’s a week for that class, so 40 hours. Robots, it’s another week for that school and then on the job training is probably the bulk of it. So hours and hours and hours of it.”