Two men in New River, Arizona were arrested Tuesday afternoon on suspicion of felony animal cruelty when it was discovered they caused the death of one horse by an injection of pool acid and starved another horse.

Detectives with Maricopa County Sheriff's animal crimes unit believe John Henkle, 54, injected a 26-year-old Arabian horse with a homemade injection of pool acid and sodium bicarbonate, causing an extremely painful death in early March, according to a press release. Laurel George, 54, is accused of assisting Henkle. According to the release, deputies also seized another horse, alive but very thin and malnourished, and took him to the MASH unit, where Maricopa County inmates care for animals from cruelty and abuse cases.

Henkle and George both share an address and both were booked into jail on two counts of felony animal cruelty, two counts of misdemeanor animal cruelty, and one count of felony animal cruelty causing protracted suffering.