Chemist at NY’s Cornell University have identified the contamination in Menu Foods’ tainted pet food supply as aminopterin – a former cancer drug, abortion drug and illegal rat poison. The wheat gluten that contained the poison was identified as coming from China. Andre Rosowsky who is a chemist at Boston’s Dana Farber Cancer Institute speculated that a rare and highly controlled substance like this would not reasonably find its way into wheat gluten unless it was put there intentionally. At this point it looks very likely that the pet deaths were intentional.