Sounds like 'Strange Days at Blake Holsey High'

I've only seen a couple episodes of Strange Days of Blake Holsey High and there are a couple similarities but a few differences too. They don't having any teacher helping them and there is no consistent antagonist. It's kind of like the Encyclopedia Brown book series.

Shawn: "I solve a case every week and usually one around Christmas"

They do share similar qualities. One of the main premises of both shows are the educational undertones. Unnatural History aims for historical and geographical references while Blake Holsey High aimed for science. UH's target demographic seems to be for young teen boys. There's a lot of action and stunts. And the first episode was centered around a murder mystery. There's occasionally gun violence and fight sequences (sometimes involving weapons). I don't recall SDaBHH ever once involving guns or fight scenes.

I like both shows, though. I really miss Blake Holsey.