If you looked at Harry's memory of the rite, like Draco did, do you think you'd see anything about Lucius that would tell you if he WAS part of the plan?

If you seriously want to be a councilwitch I think you should look at that memory because it would show you what you're getting into the sort of thing they have to do.

Mr Mulciber had to cut out a man's heart. With a knife.