Arcadia, California—A second horse in two days and 29th overall since the racing season started in December has died at Santa Anita Park, where management has chosen to continue racing for the rest of the current meet. Animal activists returned to the track this weekend upon hearing of the two deaths.

CBS News reported in May that a CBS Los Angeles investigation revealed more than 60 horses have died at the Santa Anita race track since the beginning of 2018. In March, CBS Los Angeles reported that the Los Angeles County district attorney's office had assigned a team to investigate the recent increase of horse deaths at the Santa Anita Park racetrack.

On Sunday, Truffalino collapsed in the final stages of the third race on turf. A track spokesman says the 3-year-old filly died of a heart attack.

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She was trained by Hall of Famer Richard Mandella and was ridden by Joe Talamo. Truffalino had one win in six career starts and earnings of $53,602, according to Equibase.

A man walks at the Clockers' Corner next to the empty main track at Santa Anita Park on March 10, 2019, in Arcadia, California. Getty

A day earlier, Formal Dude pulled up in the 10th race and was vanned off the track after breaking down nearing the finish line. Tiago Pereira was aboard the favorite trained by Phil D'Amato. The 4-year-old gelding was winless in six career starts and had earnings of $15,127, according to Equibase. Formal Dude was euthanized.

On Sunday night, the California Horse Racing Board asked Santa Anita to shut its doors for the rest of the season. But the track has chosen to remain open. The activists returned yesterday to demonstrate outside the track, one day after Formal Dude was put down.

"No matter what they do, horses keep getting killed here, it needs to stop," said activist Heather Wilson.

The California Horse Racing Board (CHRB) has recommended that the track suspend the remaining days of its meet, which is set to end June 23. However, Santa Anita management has chosen to continue racing.

Animal-rights advocates protest beside the entrance gate at the Santa Anita Racetrack in Arcadia, Calif., on April 6, 2019. Getty

The racing board doesn't have the authority to suspend a race meet or remove race dates from a current meet without the approval of the track operator or without holding a public meeting that requires 10 days' notice. The CHRB recommended that Santa Anita suspend racing but allow horses to continue training, believing it would provide the industry extra time to fully implement announced safety initiatives.

"It is our understanding that Santa Anita management, after consultation with certain other industry stakeholders, believes that for a variety of reasons, the future of California racing is best served by continuing to race," the racing board said in a statement.

In providing Santa Anita 10 days' notice, the CHRB may be able to shut down the track for the last three days of the meet. Santa Anita has enacted a series of reforms aimed at improving safety, but despite its efforts and a six-week stretch in which no horses died at the Arcadia track, more deaths have occurred.

"Either the rules aren't strong enough or the rules aren't being followed, but whatever the reason for the deaths of two more horses, Santa Anita needs to listen to the California Horse Racing Board and shut down," said Kathy Guillermo, senior vice president of People for the Ethical Treatment of Animals.

Santa Anita is scheduled to host the Breeders' Cup world championships Nov. 1-2.