Why Voldemort Killed Harry's Parents?

The short answer to your question is that that Voldemort killed Harry's parents because they were in the way. ... The prophecy scared Voldemort, who then targeted Harry Potter as the child that the prophecy described. When Voldemort went to kill Harry, Harry's parents tried to protect themselves and their son.

What was the reason Voldemort killed Harry's parents?

The reason Harry's parents were murdered by Lord Voldemort was because he was able to find their hiding place after their Secret Keeper Peter Pettigrew betrayed their location and broke the Fidelius Charm.

Why did Voldemort think Harry was the chosen one?

After Harry heard the full prophecy in Dumbledore's Office, he had to live with the knowledge that he would have to kill Voldemort in the end. ... Indeed, Harry was the "The Chosen One" because Voldemort chose to believe that the prophecy was talking about Harry, the half-blood like himself and thus his equal.