If the school is still talking to students and investigating what happened, then of course it would be stupid of them to say anything to parents. For something a bit more serious or more complicated than just someone getting pushed over on the playground, it can take a couple of days. If an adult didn't see it, you need to ask people who did see it. Ask 5 kids and you'll get 5 completely contradictory stories.
I've seen too many cases of hot headed Neanderthal parents having a go at teachers when an incident happens, reacting to any piece of info they get from the teacher, sometimes even confronting the other student themselves! Then once the incident was investigated wrong or misleading info was given out originally.
(This info is general in nature, and in no way related to tripper or Booneys cases)