This is known by evidence found on the skull of the individual.

They were afraid to hit a man on the skull.

She held a large rock high over her head, ready to bring it down on his skull.

I feel its dear little feet running on my skull!

He heard a quick step next to him, then felt a blow on his skull.

Given the location, so high up on her skull, I'd guess this isn't from a fall.

"Though he will be in pain for the crack on his skull."

Instead, he raised his staff and brought it down on the creature's skull.

That must be how I got this lump on my skull.

But all I could remember was the fly crawling on the skull.