I also like other approaches...attractive monetary bounties on their heads. Rely on their base human natures to cause division in their ranks. 10,000,000USD and asylum in our country in exchange for the head off a list of cartel bosses we want. Deliver it to any US embassy and once the kill is confirmed, you get the money and passage to the US.
But I do think our first response to violence like this should be a smoking crater at one of their homes. Actually, all their homes just to make sure we got the right one.