a- if i had more evidence than a suspicion and lack of other suspects...
b- if that wouldn't create unwanted friction between him and the tenant that i do volunteer work with.

if i had evidence, that i could present in court, that it was him, then i'd plough through (b) and let the chips fall where they may. as a purely practical matter, i need something more solid than "i can't think of anyone else who would've gone through the trouble" before taking it to a disputes tribunal (small-claims court).

edit: i don't even have hearsay or circumstantial evidence that it was him.