A question about moaning Myrtle being the first horcrux.

READ FIRST: I MEANT HE USED HER DEATH TO MAKE HIS FIRST HORCRUX

This isn’t me trying to make a plot hole or anything. This is a question for learning purposes only.

Okay so how a horcrux works is a person has to kill someone else. Killing someone is splits the sole and thus a hocrux is made. That’s pretty simple.

But from my understanding, isn’t it the one who makes the horcrux have to be the killer?

Because one Myrtle wasn’t killed by Tom Riddle. She was technically killed by the Basilisk stared.

Also if I remember right, Tom didn’t even actually plan to kill her. She just so happened to be in the wrong place at the wrong time. Like he never ordered the basilisk to look at the stall while waiting for her to come out.

She said, she heard a word language and then realized it was a boy and opened the stall door to tell her to go away and then it just happened.

He used her death to make his first horcrux

If he didn’t know 100% she was in that bathroom at that time, and she just so happened to be and died….

Does that count as a murder? I mean he didn’t care she died and if it hadn’t been her it would have been someone else.

But at what degree of murder does it have to be to count to make a horcrux. How planned does it have to be.

I sound psychotic trying to ask what is the definition of murder for a horcrux. But again all the other deaths he clearly planned but it seems that with Myrtle it was simply she picked the wrong bathroom to cry in and made the mistake of walking out the stall at the wrong time.