Prosecutors have said that Joseph Czuba, 71, targeted 6-year-old Wadea Al-Fayoume and his mother because of their Muslim faith amid the ongoing war between Israel and Hamas.
"Not guilty" doesn't necessarily mean "innocent". Often it just means "not confessing", ie the prosecution has to go through the motions to prove he's guilty.
Prosecutor: "The defendant is charged with murder."
Judge: "How do you plead?"
Defendant: "Not guilty, your honor."
Judge: "Okay, the trial will begin on..."
In the US justice system the defendant is presumed innocent until they either plead guilty or the prosecution proves that they are guilty. That's just how it works.
Not exactly. It's more like asking the defendant, "Do we have to prove you are guilty, or are you going to save us the effort?"
You are free to answer "Not guilty" even if you did it. It doesn't mean "I'm innocent", it means "I'm not admitting guilt". In other words, "Prove it".