>> reporter: assault rifles drawn. the team swarmed down on this colorado springs house. inside, a teenage girl and father, bound and in critical danger, or so they thought. >> i am armed with a pistol and i swear to god i will kill these people. >> reporter: it turned out, it was all a hoax. one of hundreds of incidents each year of cyber criminals hacking into phone lines and placing false 911 calls. it's called swatting, prank emergency calls so violent sounding they provoke a s.w.a.t. team response. >> hunter had been stabbed and parents and other people were being held hostage at the house. >> reporter: 15-year-old hunter told cnn how a swatter hacked into his xbox and used the game's internet connection to type a message to 911. >> i come out of my room, they got guns pointed at me. i'm like, oh, my god, i'm going to die. >> reporter: swatters are young computer hackers working alone or in groups. they often choose their victims carefully, although sometimes