Rampage was already a villain, although he had somewhat reformed.
You could argue for Jigsaw. He was a bog standard mobster prior to Frank cutting him up and turning him into a true psychotic and his long standing nemesis.
I cant recall an example of Franks actions turning a true innocent into a costumed villain though.
True, there really isn't a true innocent that became evil because of Frank. Rampage is closest one since he was somewhat reformed and Frank was completely at fault here.
Jigsaw isn't a good example as he was still a mobster when Frank through him through the glass. If he was a reformed mobster on his why out then maybe but in Rampage's case, Frank murder his girlfriend and hide the fact that he did.