Killed by clothing.
It’s not that she killed herself, it’s that her clothes drank themselves silly and pulled her from the water into the mud.
Murderous dress? Not exactly.
Just careless cloth that soaked up too much and let itself get so sopping it pulled a poor innocent singing woman into the muck.
This is a good reason to watch what you wear. You don’t want your outfit turning on you at the inopportune moment and killing you by accident.