Exclude category from comments (or enable only 1)

Is there a way to exclude a category from having comments? Or to only include one category?

I am running a magazine theme which uses categories to submit recent crimes (which need to NOT have comments or else people will leave tips about the crimes). However, we also want to set up more of a blog feature where the detectives can write whatever they want, and make that part open to comments.

I could make the blog a subdomain of the site, but then I need to find out how to feed the blog posts to the main site’s categories..

I AM looking for solutions for this, so please don’t just tell me to read up. If you can help my search go faster by pointing me in the right direction, that would be helpful.

Thanks.