My big sister killed me
My little sister hanged me
I killed my big sister

That was all her dead brother had written in his diary
He'd gone out, saying he'd be back soon, but he'd never returned
Soon after, they found his bloody hat
Left alone in the house, "I" spent each day in solitude
Having lost her only relative, everything around her began to warp as she started to lose her grip on reality

The creaking hallway. The laughing doll in her dream. The foggy memories. The brother who'd been beaten to death. The sketch of the hanging left in her brother's diary

And then, one rainy night
She woke up, realizing that
There was someone in the house
And the night with no dawn began

What did I do?
Or, rather, what have I forgotten?