Alan Johnson said UK and US authorities were working on ways to flag up when a convicted sex offender goes online. It follows the sentencing of Peter Chapman, 33, on Monday, to a minimum of 35 years for the kidnap and killing of Ashleigh Hall in Sedgefield in October. The sex offender contacted her via Facebook. The Lib Dems have also called for better internet monitoring.
Find out more about ITU's Child Online Protection Initiative