Summary: Announced, no further details
well, found a little:
8:33PM PT – Law enforcement sources confirm police responded to an incident involving Hayden today and there is currently an open investigation.
8:20PM PT – A source close to Hayden tells TMZ … she recently had been complaining about back pain in the past year.
Nashville was quite successful, I believe and she was more of a central character, where heroes was more an ensemble. She had her issues, but her career continued.