Syracuse/Rochester, N.Y. - David Renz was charged in January with possessing child porn and was released with a GPS electronic monitoring device on his ankle.
Even the judge at the time expressed concern about releasing Renz with this device because of his "technological knowledge."
Now, authorities confirm Renz dismantled his GPS ankle bracelet and managed to put it back together in a minute, avoiding a serious alert to police.
Police said then Renz accosted a mother and a 10 year-old child leaving a mall in Clay, New York, outside of Syracuse.
He allegedly stabbed the mother to death and raped the child.
Probation Officials in Western New York call this case "horrifying."
They said while it's impossible to predict someone's behavior, they believe in most cases the monitoring bracelets are effective.
163 federal suspects in Western New York were released with these monitoring devices in 2012, and US Marshal Chuck Salina said there were no serious incidents. "We've been very successful here with it," he said.
Salina said though there were individuals who have tampered with the bracelets. "There have been individuals who have cut the bracelets, I recall one that decided he would take it off and he fled to North Carolina. That's where the U.S. Marshals Office comes in, we track down fugitives all over the world."
Salina said he isn't familiar with the monitoring device that David Renz had and doesn't know much about the case.
He also said these monitoring devices don't work for everyone.
It's up to the judge to decide if they are a secure form of release for suspects.
Salina said he believes the monitoring devices are a deterrent in most cases because he most suspects don't want to go back to jail.
If they do tamper with the unit, an alert goes out, a judge issues a warrant and the person becomes a fugitive.
The Marshals then track them down and they are sent back to prison.