Because you already told me. WHY DON'T YOU BELIEVE ME?
It is lying and/or manipulating, but you're telling someone that they first told you it happened. Yeah there's a limited difference but I guess it depends on context.
What you did was lie. Poorly apparently
. What you needed to do in order to gaslight him was convince him
he was the ringleader. Then he would have confessed to it and you'd have just unfortunately been involved.
It's not the circumstances I gave in my earlier post, but it's the concept, as I understand it.