Cruz was a fluffy marshmallow of a dog, a prizewinning Samoyed who flew commercial, not in the cargo hold; scarcely touched the sidewalk; and competed at this month’s Westminster Kennel Club Dog Show.

On the eve of the competition, Cruz shared a steak with his longtime handler and settled in for the night at a hotel in Midtown Manhattan.

But before the week was out, Cruz was dead, and his snow white body was at the center of a high-stakes mystery, a whodunit that has rattled the show world and ignited tensions between animal activists and purebred-champion breeders.

Cruz’s survivors — the handler and at least one of his owners — have not ruled out foul play.

They have spent the days since his death retracing every paw step, replaying conversations with onlookers, racking their brains to understand what happened.