Such fatalities were supposed to be prevented by the involvement of the American Humane Association (AHA).

FORBES: Horse Deaths Won't Stop Production of HBO's "Luck"

Barbara Casey, ex-director of the American Humane Association film and production unit, says producers "engaged in ongoing, systematic and unlawful animal abuse".

BBC: HBO sued over cancelled show Luck

Ms Casey's lawsuit also accuses the American Humane Association (AHA) of bending to pressure from the TV network "to allow the use of unsuitable horses".

BBC: HBO sued over cancelled show Luck