The 15-year-old Standardbred cross horse died due to a small tumor in her adrenal gland that likely caused an aortic rupture, a necropsy found, a TWU representative said.

This story contains details that may be disturbing to some viewers. NEW YORK (PIX11) – The cause of death for a carriage horse that passed out and died on a Hell’s Kitchen sidewalk has been released,

TWU Local 100 said the carriage horse's cause of death was determined following a necropsy at Cornell University Collage of Veterinary Medicine.