South Texas Trail Riders' two horses that died had ingested anti-freeze

SAN ANTONIO, Texas (KTRK) -- The South Texas Trail Riders have released what caused the death of two horses while on the annual trail ride to San Antonio. Toxicology tests show the two horses ingested anti-freeze.

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The group posted on its social media accounts warning trail riders to stay cautious if they were parked at the Martinez Hall around Feb. 9.

According to the group, one of the horses was found dead while the other had to be put down.

The trail riders have filed a police report with the San Antonio Police Department. An animal cruelty investigator is assigned to the case.