Simplify the following text for a Grade 9 native English-speaking person.
Original: In 1968 Baader and his girlfriend Gudrun Ensslin were convicted of the arson bombing of a department store in Frankfurt am Main to protest the public 's `` indifference '' to the `` genocide '' in Vietnam .
Simplified: In 1968 , Baader and his girlfriend Gudrun Ensslin were convicted of the setting fire to a department store in Frankfurt am Main .