No one can die without the permission of God. God know everything and He see everything. He is in charge of the affairs of men. He hold the the breath of breath of all mankind. He can give life and He can also take a life.
Job 12:10 In whose hand is the soul of every living thing, and the breath of all mankind.
God is aware of every activities going on and He knows every soul that was lost. Someone can only die because God permitted it. Jesus liken us to a sparrows. No sparrow would die without God knowing. A sparrow is a very small bird and it is sold for a very small price. Yet God knows every sparrow and holds their life in His hand. If God knows every sparrow that are not expensive. How much we human. Are will not important than a Sparrow?
St. Matthew 10:29 Are not two sparrows sold for a farthing? and one of them shall not fall on the ground without your Father.
If a person is killed willing or accidentally, it is because the person time up. Everyone has their owns specific time to die but the process which will occur differs. Some might be a peaceful death while might be through an unfortunate event. Like accident, gunshot and the likes.
Hebrews 9:27 And as it is appointed unto men once to die, but after this the judgment: