Four horses have died in less than a month at a racetrack in California.
The latest death was that of a 3-year-old filly named Bri Bri, the Del Mar Thoroughbred Club said in a statement Monday.
Bri Bri, who was unraced, was euthanized after suffering a serious pelvis injury during training, the statement said.
The club says it is meeting with the horse's trainer, Jim Cassidy, to discuss the incident.
Three other horses died at the track last month. None of the four fatal injuries occurred while the horses were racing, the club said.
Bowl of Soul, a 3-year-old filly was euthanized after sustaining an injury to her hind fetlock, a joint similar to an ankle, while training on July 29, according to the California Horse Racing Board.
Following her death, Del Mar Thoroughbred Club spokesman Mac McBride said the track had policies in place that made it "among the safest in the country."
Two other horses, Charge A Bunch and Carson Valley, died in what trainers called a "freak accident" after colliding on the track during a July 19 training.
It happened after Charge A Bunch threw off rider Geovanni Franco and made a U-turn. Then, running the wrong way along the track, Charge A Bunch ran into Carson Valley.
"This was a very unfortunate accident and it is a shock to everyone in the barn," Carson Valley's trainer Bob Baffert said in a statement following the deaths.
Baffert was also Bowl of Soul's trainer, according to the Del Mar Thoroughbred Club.
People for the Ethical Treatment of Animals, or PETA, called for a full investigation into the deaths of the horses in a statement Monday.
"Trainer Jim Cassidy owes the public an immediate explanation, as does trainer Bob Baffert, whose horse Bowl of Soul died less than two weeks ago," PETA said. "It's time that trainers came clean about what condition their horses are in, what medications they're on, what treatments they may have had to block pain and keep them running when they shouldn't be."
The deaths at Del Mar come after 30 horses died in less than a year about 100 miles north at Santa Anita Park in Arcadia, California.
In June, California Gov. Gavin Newsom called for Santa Anita to have its horses examined by independent veterinarians before they race.
"I continue to be troubled by the horse deaths at Santa Anita Park. Enough is enough," Newsom said at the time. "As Santa Anita prepares to host the 2019 Breeders' Cup in November, we must show the horse racing world that California puts safety first."