Probably got run over while playing in the street, or were picked up for animal testing.
I doubt both of those, our cat never went near the street. it was probably either the neighbor's dogs (although I doubt that too, I'm just considering it because my mom claimed that they "tried to eat the cats" one time. I doubt it because I played with them once and they were really nice, and one of them would even sit when you told him to. it doesn't seem like they'd attack anything), or a neighbor "rescued" them because so many people seem to think that if a cat is outside without a collar, it's a stray
