Predator Martin Scougal was detained for four-and-a half years in 2012 for raping one girl from the age of nine and molesting another child from the age of about eight.
Scougal was 12 when he first began abusing the rape victim and 14 when he started having sex with her at a house in in Berwickshire.
But he stood trial again at the High Court in Edinburgh earlier this year for another catalogue of sex crimes involving further victims which began in 2010 when he was 18. He raped another girl aged 13 in Berwickshire and a 14-year-old in Peebles.
Judge Lady Wolffe told Scougal, now 22: "You have been found guilty of nine charges involving sexual misconduct towards two girls, which include five charges of rape."
Scougal, of Ayton in Berwickshire, was placed on the sex offenders' register.