The Well

One day I killed my little sister because she annoyed me.
I threw her body down the well.
The next day when I checked the well, the body had disappeared.

Five years later I killed my friend after a row.
I threw his body down the well.
The next day when I checked the well, the body had disappeared.

Ten years later, I killed a woman I got pregnant in a drunken daze.
I threw her body down the well.
The next day when I checked the well, the body had disappeared.

Fifteen years later I killed a boss I hated.
I threw his body down the well.
The next day when I checked the well, the body had disappeared.

Twenty years later I killed my mother because she had become bedridden and I didn't want to look after her.
I threw her body down the well.
The next day when I checked the well, the body had not disappeared.
And the body remained there for days - days and days and days.

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Amanojaku : Why do you think the body didn't disappear at the end?