[Spoiler] Make your own conclusion on how exactly Menma died.

Manaban said:
All I remember is that there was a scene that kind of tied it to a river so I assume she had an accident and drowned.

Also, hello, I work in the funeral industry and the main reason I'm making this post is to remind everyone that when somebody drowns, their body fills up with the excess liquid that they'd taken in - and on top of that, if it's in a natural river and not something loaded with chlorine like a swimming pool, there's a fuckton of bacteria. The amount of leaking that can come out of a drowned cadaver is rather insane. Not just like, their anus, but their eyes, ears, literally anything with a slight opening has the possibility to just start gushing like a well. And the way that it interacts with the extreme amounts of bacteria - as would be present in a natural river - can often result in fascinating things happening with that liquid that gets stored up in the body.

A funeral I had worked with somebody who drowned in a lake began leaking brown and red goo from their ears and eyes, as an anecdotal example, because of the overflow of liquid + the bacteria + natural blood.

On top of this, that riverbed was shown to be decently rocky and fast, meaning she likely had a lot of lacerations and bruisings from the rockbed, making the way she would've appeared on the table even more gruesome due to external injury caused by getting thrown around by a fast moving riverbed. She would've been leaking out of every orafice in her body on top of having a heavily damaged exterior.

Just wanted to share this have a nice day