LOS ANGELES (AP) — A horse was injured and euthanized Tuesday during production of the racetrack drama “Luck,” the third death in connection with the series, and HBO agreed to suspend filming with horses while the accident is investigated.

The humane group that oversees Hollywood productions had issued an immediate demand “that all production involving horses shut down.”

“We are also insisting that this stoppage remain in full effect pending a complete, thorough, and comprehensive investigation,” the American Humane Association said in a statement. It noted that the accident didn’t occur during filming or racing.

The animal was being led to a Santa Anita Park racetrack stable by a groom when it reared and fell back Tuesday morning, suffering a head injury, according to HBO. The horse was euthanized at the track in suburban Arcadia, where “Luck” is filming its second season.

In the series, which was created by David Milch (“Deadwood,” ”NYPD Blue”) and looks at racing’s seedier side, Dustin Hoffman plays a crime kingpin who’s scheming to gain control of a racetrack and introduce casino gambling.

The American Humane Association’s film and TV unit, the group sanctioned and supported by the entertainment industry to protect animals used in filming, called for a production halt at the Santa Anita Racetrack in suburban Arcadia after the second horse’s death.
Racing resumed after new protocols were put in place and proved effective, Karen Rosa, the AHA unit’s senior vice president, said in February.