Honestly, I wouldn't put it past the Mossad to do it, or at least do it once publicly as a warning to others.

They've been known to assassinate families and even prostitutes of targets as well as the targets themselves.

Generally, they probably just mean the standard Hamas fighter running around aloha snackbaring while people are getting fucking lit up, so I'm not upset about that. But I would not think that murdering an AP journalist was beyond them.