For most Americans, cell phones are a way to keep in touch. But for prison inmates, they're a way to call in a hit from behind bars. While it seems as if inmates will stop at nothing to keep in touch with life outside prison walls, Capt. Robert Johnson of the South Carolina Department of Corrections and his contraband squad are on the job.
Johnson has witnessed cell-phone-strapped bazookas being blasted over prison fences. He's even seen flying footballs with wireless surprises hidden inside. When Johnson's teams search the living and work areas of South Carolina State Prison inmates, they often recover cell phones.
A contraband cell phone almost cost Johnson his life -- an inmate used one to call up a hit on the captain.
"An inmate who had a cell phone called an ex-inmate and set-up a hit on myself," Johnson told "Good Morning America."
The hitman shot Johnson six times in the chest, but he managed to survive.
"I guess the Lord just said this guy is just too ornery to die," Johnson said. "I'm going to let him live. And I lived."
Johnson's story is unfortunately just one of many, as a long string of crimes has been traced to inmates possessing illegal cell phones.
In 2007, Patrick Byers, 25, ordered a hit on Carl Lackl a week before he was scheduled to testify against Byers in a murder trial. Byers used an illegal cell phone from inside a Baltimore jail to put out a hit on Lackl. One unsuspecting summer day, Lackl was gunned down outside his house during a drive-by shooting. Byers was sentenced to life in prison without parole.
Convicted mass murderer Charles Manson was also caught with a cell phone in California.
And in Texas, Richard Tabler, an inmate on death row, got hold of a cell phone and used it to repeatedly threaten a state official. In California alone, 9,648 cell phones were taken from inmates in 2010.
A few state prison systems have responded to the security threats, and corrections officials have taken matters into their own hands. Prisons are using cell phone sniffing dogs, body scanners and other technology to hunt down illegal cell phones.
Cell Hound, for example, uses sensors placed around the prison to locate calls in real time. It can pinpoint the location of a phone within three jail cells, but only six states use it.
Another system, Managed Access, acts like a cell tower for the prison. If a call comes from a number on the approved list, it goes through. But if it comes from an unrecognized cell phone number -- for example, an inmate with a smuggled cell phone -- the call will be blocked, and that inmate gets a rejection message saying "the celluar device you are using has been identified as contraband."
Managed Access operates only in Mississippi, but since its inception last August, it has intercepted more than 600,000 attempted illegal calls from inmates, according to state prison officials.
ABC News' Amanda VanAllen contributed to this report.