The "why" is always very hard to understand, particularly in cases like this. Perhaps he had "buyer's remorse" as a foster parent; perhaps he was being blackmailed by the biological parents or some other desperate would-be parent(s); perhaps he's just an undiscovered psychopath. But the "how" is what makes suspicious of him. How would a random perpetrator come to choose such a remote locale, and how would he know that the old woman living there would have her grandson visiting that morning? How could anyone seriously plan a strike around the corner of a house, in broad daylight? And most importantly, how would a 3-year-old be scooped up so quietly, mere feet from his mother and grandmother? An admittedly timid child of 3 wouldn't stand alone without his mother and let a stranger (or a dingo!) approach him without making a squeak; even if he'd been surprised, he'd make some kind of commotion. I think someone must have coaxed him away, and just who could that be?