R. v. Carpio, 2012 BCCA 484 is a useful source for the view that where there is a lot of smoke one can conclude there is a fire:
 As was said in R. v. Jenkins (1908) 14 C.C.C. 221 (B.C.C.A.) at 230:
It is true that a man is not called upon to explain suspicious things, but there comes a time when, circumstantial evidence having enveloped a man in a strong and cogent network of inculpatory facts, that man is bound to make some explanation or stand condemned.
 I consider this observation apposite in this case.