Sorry for your loss, but without a necropsy it is impossible to finger the product as the cause of death. Please don't take offense, but in all fairness it is possible that your kitten could have died by another means. Without the hard technical evidence one cannot say for sure it was the Hartz product. Again my condolences as a cat owner I'd be beside myself if my Willard died under these circumstances. I would also take him to my vet for a proper necropsy to find out the scientific truth before accusing a person, entity or business of taking his life. But that's just me..