ARCADIA (CBSLA) – Yet another horse died at the Santa Anita race track in Arcadia Monday morning, bringing the death toll to 19. Officials shut down the main track to racing through at least Tuesday to attempt to diagnose what may be causing the problem.

Charmer John, a 3-year-old gelding, had to be euthanized Monday after suffering an injury to his left front fetlock, according to the Los Angeles Times. He is the nineteenth horse to die at the track while racing or training since Dec. 26, according to the Times.

Horses workout on the training track at Santa Anita. Feb. 26, 2019. (CBS2)

On Sunday, Santa Anita announced that it would be closing the main track beginning at 9 a.m. Monday and all day Tuesday in order to “fully evaluate sub-surface conditions such as moisture content and soil consistency.”

The training track, however, will be open through 10:30 a.m. all week.

According to the Times, Santa Anita’s owner — The Stronach Group — allowed the main track to be open until 9 a.m. Monday for early-morning workouts after several trainers objected to its closure. 121 horses trained on it during that time, the Times reports.

Santa Anita brought in Dr. Mick Peterson, director of the University of Kentucky’s Agricultural Equine Programs, to lead the evaluation and tests.

Experts will look at whether the heavy rainfall which has fallen across the region over the past few months has factored into the death toll. Santa Anita has so far received 11 ½ inches of rain this season.

Track Superintendent Andy LaRocco and his crew will be peeling back the track’s cushion to a depth of five inches to do the examination.

During this same two-month period in the 2017-18 season, 10 horses died at Santa Anita. Eight died in the 2016-17 season and 14 died during the 2015-16 season, the Times reports.

The track is expected to be back open for training on Wednesday and live racing on Thursday.