I'm home, read the newspaper again, and yes, you're right about Ment, he seems to be either a class representative or a nerd.

I didn't find anything good. Except for Nebo (aka Olam Havel) in his profile, the inscription says "We will drive humanity to happiness with an iron fist!" -> jelly -> cooking.

I looked at the profiles, I agree. The cookbook is a direct indication of the murderer, and the cognac and refrigerator are for fun, I think they fit. If we judge very straightforwardly, then it's Olam Havel, who drove Ment into the army with an iron fist. Here are some other options from Google: Several chefs named Alex. There's a choice for every taste. Hexane is used in the extraction of vegetable oils and as an organic solvent.