Might be late to the party, but I figure I can throw out some team name suggestions.
Along the same vein of the Denizens, perhaps the Delvers since we are going to spend a lot of time investigating a mystery.
For a mouthful but also sort of fun, the Research Club for a bit of a school theme. Also the Study Hall Five, which could just be SH5 in most cases. Study Hall Six would be better alliteration, but we don’t have six members unless someone picks up a wacky animal companion… hint, hint.