Food thief in the office

Over the past few weeks we have had frequent emails in the office regarding the disappearance of various people's foodstuffs in the upstairs kitchen. We have pretty small work areas here, and of course we only have the shared refrigerator upstairs, so most people keep their snacks, left-overs, and drinks in the shared kitchen space. Apparently someone considers everything in the shared kitchen space to be fair game for shared consumption. Here are a few excerpts from these emails:

3 weeks ago:
[french office] pain au choc stealer
Celui qui me vole regulierement des pain au choc sera prié de m’en racheter et la prochaine fois, au moins de prévenir quand il tape dedans

basic translation: Whoever keeps stealing my pastries needs to buy me some new ones.

2 weeks ago:
Those cokes in the fridge are not for everyone, please stop drinking my cokes.

1 week ago:
title: Milk in the fridge
body: The milk isn't free either, a**holes

and the most recent:
steal my food = kick in your a** so hard you will not be able to sit for 3 days.

A couple of things stand out to me about these emails. First, the are becoming progressively more hostile (presumably as people keep stealing food), and second they have switched from scolding their coworkers in French to scolding their coworkers in English.

We have a company policy of sending important emails in English. We are currently working with a German company and an American publisher, and we have a satellite office in Austin, Texas, so it just makes everything easier when emails are in English. For emails that only involve people in the french office, however, French is more often used. I doubt the guys in Austin are drinking the milk in the french fridge, so as these emails became more hostile and more English, I couldn't help but notice that I am the only guy in the office who isn't fluent in French. Do they all think I am stealing their snacks?

It's not me man, I swear. I don't even like chocolate, french milk is still weird to me (so I only drink it with cereal) and I prefer pepsi to coke.