The court heard Rees had befriended the girls' father
A former Birmingham teacher has been jailed after admitting indecently assaulting two pupils during after-school homework sessions.
Brian Rees, 66, of Farm Road, Oldbury, West Midlands, carried out the assaults in the late 1960s and early 1970s.
The two victims - sisters aged between eight and 13 - were pupils at Barford School in Ladywood.
Rees was sentenced to 18 months for four counts of indecent assault at Birmingham Crown Court on Friday.
The court heard how Rees had groomed the pupils, buying them gifts, and abused them at an address at Gillott Road, Edgbaston, his home at the time.
Neither sister realised the other had also been assaulted until a recent television documentary about sexual abuse prompted them to tell each other what had happened.
They reported the abuse to West Midlands Police and Rees was arrested on 19 September.
The court heard Rees had befriended the sisters' father in order to build up a rapport with the family.
'Lifetime of torture'
One sister said being in Rees's junior school class for three years was "mental torture".
In her victim impact statement the woman, now 51, said: "He ruined my childhood and I woke every day not wanting to go to school."
Her older sister, now 55, added: "Throughout my life I've not felt able to go in the street he lived or near the school as it brought back the memories.
"I used to walk the long way home from school so as not to pass his house. Sometimes it meant arriving home late and I would be told off, but felt I couldn't tell them why.
"I have lived a lifetime of torture and Rees must acknowledge this."
Det Sgt Jayne Killoch said: "These offences occurred decades ago but, as several high-profile cases have proved recently, it's never too late to contact police.
"Rees has also suggested he indecently assaulted two other girls at the school − friends of the sisters − and we are actively trying to identify and locate them."
Rees was also ordered to sign on the sex offenders register for 10 years and barred from working with children.