They were serving an arrest-warrant for a man accused of child-porn; and this is what happened.
As far as I'm concerned, this is why LE often has to use force to get a situation under control to avoid additional violence b/c LE often doesn't know what kinda person they are dealing with - the murdered agents were 43 and 39 ys/o.
This is the kind of violence, and kind of people, LE often has to deal with - sure, not everyone that LE deals with is violent; but LE often does not know how a person will react and why IMO they have to do what they have to do to take control of a situation rather than "letting play out" - then at times they are accused of excessive force when they are usually trying to avoid situations like this - not saying there aren't any cases of excessive-force; just that too-many times LE is accused of excessive-force when they are trying to get a non-compliant perp to comply in order to avoid incidents like this that most of us civilians do not deal with:
Going to withhold judgement until the full facts are released. It's a tragic event.