Another horse died at Santa Anita Park in Southern California on Saturday — the 30th since Dec. 26 and the fourth this month — prompting the owners of what has become one of the deadliest racetracks in America to bar Jerry Hollendorfer, the horse’s Hall of Fame trainer.

American Currency died after a training session Saturday. The horse was the fourth trained by Hollendorfer to die at Santa Anita Park since the meeting opened on Dec. 26.

The spike in fatalities at the landmark racetrack has put a bull’s-eye on the very existence of one of America’s oldest sports. The deaths have prompted an investigation by the Los Angeles County district attorney’s office and earned public rebukes from Gov. Gavin Newsom of California and Senator Dianne Feinstein, Democrat of California.

The Stronach Group, which owns Santa Anita and six other American racetracks, has blamed corrupt trainers and owners for the deaths, which have dominated national headlines and imperiled the sport nationally.