The alarming number of horse deaths at a California racetrack has drawn the attention of the Los Angeles District Attorney’s Office, which has announced it was conducting a criminal investigation with state regulators.

The DA investigation has been prompted by the deaths of 22 thoroughbreds at Santa Anita Park since Dec. 26 and is being conducted jointly with the California Horse Racing Board, according to a Reuters report Friday.

The deaths of the horses due to catastrophic injuries suffered in training and during races over the short period of time have alarmed horsemen and racing fans and led to a renewed focus on the racing industry’s long-standing problem with drugs--both legal and illegal. These substances can mask injuries a horse may have suffered due to the stress of running on spindly legs.

ANOTHER HORSE DIES TWO DAYS AFTER CALIFORNIA TRACK RESUMES RACING; DEATHS NOW NUMBER 22

“We are cooperating fully with the District Attorney’s Office. We will not be providing any additional details about the ongoing, confidential investigation,” Shawn Loehr, CHRB chief of enforcement, said, according to KABC-TV.

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."

Santa Anita in Arcadia has canceled racing in response to the breakdown deaths.

SANTA ANITA PARK SUSPENDS RACING INDEFINITELY AFTER 21ST HORSE DIES

Some trainers have blamed the deaths on heavy rains which has affected maintenance of Santa Anita's dirt track.

On Thursday, 3-year-old filly Princess Lili B snapped both front legs during a workout, forcing her to be put down.

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After the breakdown, the Stronach Group, which owns Santa Anita, announced that two prescribed anti-inflammatory drugs will be banned the day of a race and that jockeys will not be allowed to use a whip on a horse as they compete.