Double Touch, seen here racing in the ANS Means Business Maiden Stakes, died suddenly, Santa Anita Park said.
CNN  — 

Another horse has died at Santa Anita Park, becoming at least the fifth to die at the Southern California thoroughbred racetrack this year.

The 6-year-old horse named Double Touch died Saturday on the training track, according to an incident report on the track’s website. The report described it as a “sudden death.” The cause of death has not been determined.

At least four other horses have died at the track this year, three of them in a span of three days in January.

The year started with the death of 4-year-old horse Golden Birthday, who was injured in a January 1 race.

On January 17, 6-year-old Harliss was euthanized after fracturing his right ankle. The next day, 5-year-old Uncontainable was euthanized for the same reason, and a day later 3-year-old Tikkun Olam “suffered catastrophic injuries, necessitating euthanasia” after a head on collision with another horse while training, California Horse Racing Board spokesman Mike Marten told CNN in an email.

About 40 horses have died at the track since December 2018. Officials briefly halted racing at the track last year in light of the number of deaths.

Santa Anita has since made changes in an effort to increase safety for the horses, including restricting steroids, anti-inflammatory drugs and race-day medications.

A recent investigation by the Los Angeles County District Attorney’s Office found no indication of animal cruelty or criminal activity.

The park houses 2,000 horses and is one of the largest equine training facilities in the country, according to its website. Santa Anita Park said in January that horses raced or trained at the park “more than 420,000 times over the last year with a 99.991% safety rate.”

CNN’s Theresa Waldrop contributed to this report.