If it's alright, I'm going to give a bit of backstory. In this story, Voldemort attacked the Potters after hearing a 'prophecy' from Dumbledore/Trelawney. This attack didn't kill anyone, since he stunned the adult Potters before attempting to kill Harry. Obviously this failed, and he was left without a body. On Dumbledore's orders, the attack remained secret until he needed it to be used for propaganda and power.