Why wont this admin script work?

It does everything but kill the player. I want it so that you don't need to type the full name of a player, but obviously I have failed.

players = game:GetService("Players")
admins = {["Player"] = true ; }

players.PlayerAdded:connect(function(newPlayer)
	if admins[newPlayer.Name] then
		newPlayer.Chatted:connect(function(msg, speaker)
			if string.sub (msg, 1, 6) == ":kill " then
				for _,v in pairs (players:GetPlayers()) do
					if v.Name:match(string.lower(msg, 6, string.len(msg))) then
						v.Character.Humanoid.Health = 0
					end
				end
			end
		end)
	end
end)