How about setting things up as best you can to get some footprints? Remove
the mulch from an area, flatten the soil with a board, and gently mist it.
Compare the results (if any) with the tracks on a site like this:

http://www.bear-tracker.com/

If it's a normal animal, maybe a Havahart trap is in order. If it's an
abnormal creature, like someone's useless, stinking obnoxious little dog,
then you know what to do, I assume. BAM! :-)