Most Wanted Player

Exactly

I am pretty sure it should give you the reward everytime you complete killing as "vigilante efforts" which is around $1000 - $1250 and 5score. Other than that I think it must be a bug? Never happened to me though.

Everyone should get the reward when they kill a most wanted player. If they aren't this is a bug.

I do not agree that most wanted should only be one player. The FBI has a list of most wanted suspects not just one.