ARCADIA, Calif. (AP) -- Investigators with a prosecutors' office have been assigned to help look into 22 recent horse deaths at Santa Anita, a spokesman for the Los Angeles County district attorney's office said Friday.
The investigators will work with the California Horse Racing Board as it probes the deaths, district attorney spokesman Greg Risling said.
He declined to say what sparked his office's involvement and when the decision was made.
The most recent horse death happened Thursday when a 3-year-old filly broke down just past the finish line after a half-mile workout. That marked the 22nd death at the track since the winter meet began Dec. 26.
People for the Ethical Treatment of Animals has been calling on the district attorney's office to investigate since March 1 and protested outside the prosecutors' office following Thursday's death.
PETA said in a statement that it began campaigning against cruelty in horse racing in 2008 when a horse broke both front legs after crossing the finish line at the Kentucky Derby.
"Eleven years of broken bones and thousands upon thousands of thoroughbred deaths have finally resulted in a criminal investigation into trainers," Kathy Guillermo, PETA's senior vice president, said in a statement. "The DA's office is doing the right thing."
Santa Anita spokesman Mike Willman said in a statement that the track welcomes the district attorney's "sincere interest in solving these very serious issues that we've experienced over the past two months."
He also pointed to an announcement Thursday by the track's owner, The Stronach Group, that Santa Anita will ban the use of medication and whips on racing days, making it the first racetrack in the nation to impose such restrictions.
The owner of Los Alamitos Race Course said late Friday that he will continue to allow the use of Lasix, an anti-bleeding medication, at the Orange County track where thoroughbreds and quarterhorses run.
"I believe that the continued use of Lasix is in the best interest of the horses and, as such, is a major contributor to the safety of the industry's human and equine athlete," track owner Ed Allred said. "I shudder to think of the consequences to racehorses and their riders if Lasix was banned."
Allred breeds and owns quarterhorses. He said Los Alamitos will review the reforms suggested by The Stronach Group with owners, trainers, jockeys, regulators, and other track operators.
"Obviously, everyone is interested in making those reforms that will contribute in making the sport of racing better for everyone, including the wagering public," Allred said.
Los Alamitos hosts eight weeks of thoroughbred racing a year while running quarterhorses year-round.
Since 2015, the track has had a zero-tolerance policy against Clenbuterol, Albuterol, Zilpaterol and similar B2-agonists and conducts hair testing prior to major quarterhorse stakes races.
PETA is calling on "all tracks in the U.S. to stop the abuse and carnage and enact the changes made by Santa Anita racetrack --- or get out of the business."
Meanwhile, Rep. Judy Chu, D-California, whose district includes the racetrack, said Friday that she was outraged by the horse deaths and that the track should be closed "until we know the horses are safe."
She said she was calling on the House Energy and Commerce Committee to investigate and hold a hearing on the treatment of horses at Santa Anita and other racetracks.
Santa Anita's changes came after a bill, the Horseracing Integrity Act of 2019, was introduced in Congress on Thursday by Rep. Paul Tonko (D-New York), and Rep. Andy Barr (R-Kentucky). The bill would create a private, independent authority to develop and administer a nationwide anti-doping and medication control program for the sport.