AceShowbiz -

HBO's "Luck" has just been hit with a misfortune. Another horse has been injured and dead on the set of the sports drama during the production taking place on Tuesday, March 13, leading the network to suspend filming with the animals with the accident is being investigated.

"Tragically, this morning, one of the horses in Lucks stable suffered an accident while returning to the stall," HBO said in a statement. California Horse Racing Board (CHRB) official veterinarian Dr. Gary Beck said "the horse was on her way back to the stall when she reared, flipped over backwards, and struck her head on the ground."

Attending veterinarian Dr. Heidi Agnic, who was on the set when the incident took place, administered immediate aid to the injured horse and "determined that humane euthanasia was appropriate." The horse was euthanized at a Santa Anita Park racetrack stable where the show is currently filming its second season.

The American Humane Association (AHA) has since called for a halt to filming with horses. "We are also insisting that this stoppage remain in full effect pending a complete, thorough, and comprehensive investigation," the organization said in a statement. HBO itself agreed to work in full cooperation with the AHA and the CHRB to complete their inquiry.

Two horses had been dead on the set of "Luck" during the production of the first season. People for the Ethical Treatment of Animals (PETA) expressed serious concerns on the tragedies, sending a letter to L.A. District Attorney Steve Cooley on Monday, a day before the third horse died, to investigate the situation.

Following the latest incident, the organization insisted, "We will want answers on HBO's latest casualty. Filming must stop now." Kathy Guillermo, a PETA vice president, said, "Three horses have now died and all the evidence we have gathered points to sloppy oversight, the use of unfit, injured horses, and disregard for the treatment of thoroughbreds."