Animal service officials in Texas are investigating after a dog ate a meatball laced with antifreeze, officials said.

According to San Antonio Animal Care Services, a homeowner said someone threw a meatball with "some sort of substance" over their fence last week, the San Antonio Express-News reported.

The owner said one of the dogs ate the meatball, according to KSAT. The animal was taken to a veterinarian and was not affected by the tainted meatball, WOAI reported. Officials at Texas A&M tested the meatball and discovered the antifreeze, the television station reported.

ACS spokeswoman Lisa Norwood confirmed an investigation was opened, the Express-News reported.

“A substance poisonous to animals was thrown into the yard, but why and by whom this happened, I couldn’t say yet,” Norwood told the newspaper.