Well ACTUALLY, that bullet would not have enough energy to kill anyone if it fell on almost exactly the same spot it was fired from. Bullets shot into the air can be dangerous, but not if fired straight up, only if fired at an angle. (Don't ask me the angle at which it can become deadly, i don't know and it probably depends on many factors)

If you would fire a bulltet like this, the maximum velocity it can have is the terminal falling velocity and since pistol bullets are pretty light (a few grams), it will only have enough energy to cause a bruise. If you looked staight up, maybe you could loose an eye if you are very unlucky.

It's the same as throwing a coin down a really high skyscraper. You can't kill somebody like this.

But DON'T Shoot Bullets into the air. It Won't harm YOU really. But if you shoot at an angle, it might kill somebody half a mile away.