Colombo - By dawn's early light

The protagonist is one of those guys obsessed with the military world, military discipline and of course war. I didn't like him one bit. Everything happens at a military academy, a school for boys who wants to start a military career, I think it is. This commandant, colonel Rumford, is rather obsessed with it, but the school is not doing so great, it's not even half full, so Haynes wants to turn the academy into a school opened to boys and girls alike, not a military academy, and Rumford is very much against it. Haynes has the same name of the academy because his grandfather founded it.
Rumford plans his murder, putting inside the cannon a rug to block it and also modifying the 'bullet' adding explosive, so instead of shooting blanks it explodes when Haynes fires it at the academy ceremony.
When Rumford was there in the early morning to put in the rug, he was able to see a bottle of cider hanging from a window. He could just let it go, right? Given the circumstances... but no, he immediately orders to find the culprit, appearing so sure that one of the student is making cider, rather obsessed with it he wants to find the culprit and punish him.
Colombo investigates and of course he's the one who doesn't believe it's an accident at all, and he keeps around the colonel asking questions as he always does, he also starts sleeping with the kids (well more or less, he thought he would be together with them, actually he's only in the same section of the school, but has a room of his own).
When the colonel wakes everyone up at 3am to search the rooms looking for the cider, Colombo hides it before it can be found, then he talks to the kids learning everything he needs to know about it to bust the colonel.
The cider could have been seen only that morning of the explosion. Not before (too dark) not later (it would be taken inside to avoid anyone seeing it during the day), so this proves that the colonel was right next to the cannon that early morning...
He's all 'I had to do it, I don't regret it'... well no, you didn't "have" to do it !

ITA alle prime luci dell'alba