Why are Republicans defending the killing of Alex Pretti?

One of my old school conservative friends on Facebook (not a Trump supporter) commented the above question. It seems clear to me that Pretti cooperated with ICE and was executed. I can think of a few possible explanations why Republicans would rationalize this instead of just agreeing that ICE made a mistake, but each one feels like it’s only part of the answer. What’s the heart of the matter?