Canadian serial killer who was jailed for 12 years over rape and murder of three teen girls including her sister has been volunteering at her children's elementary school

Karla Homolka, 47, was pictured outside her children's Montreal private Christian school this week (right) where she occasionally volunteers. Homolka served 12 years in prison after being convicted in 1993 of raping, torturing and killing schoolgirls Kristen French (top left) and Leslie Mahaffy (top right) with her then-husband Paul Bernardo. She also played a role in the death of her 15-year-old sister Tammy (bottom left) after she helped Bernardo drug, rape and ultimately kill her. Homolka, who split from Bernardo while in jail, was released in 2005 and married her lawyer's brother Thierry Bordelais. The 47-year-old has three children from her second marriage.