Hewlett was first convicted of raping a 12-year-old girl in Todmorden, West Yorks, in 1972.
He was jailed for a year, then got four years for attacking another girl at gunpoint in 1978.
He later served a six-year sentence for a 1988 sex attack on a girl of 14.
After leaving jail he fled to Ireland, where cops believe he was responsible for a string of attempted abductions.