No - vidur is not the killer, if he did it for some mahajan - my first guess will be DB!
Real MM is a mahajan, prem would not run away from mahajan famuly if he was framed by vidur (or any outsider) or knew something dark about vidur - he would drag him to the court or face him!!
Yeah that's what even I'm saying for long now , DB is the logical choice because no one is more powerful/influential than him , it wouldn't even make sense if Dhanraj or someone else is the mastermind...
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