Florida governor Jeb Bush has signed a law imposing tougher penalties on child molesters and requiring many of those released from prison to wear satellite tracking devices for the rest of their lives.

The measure spurred by the killing of a nine-year-old girl, signed yesterday gives Florida one of the toughest child-sex laws in the US. It establishes a mandatory sentence of 25 years to life behind bars for people convicted of certain sex crimes against children 11 and younger, with lifetime tracking by global positioning satellite after they are freed.