As reported by Debbi Baker of the San Diego Union Tribune

SAN DIEGO — A reward leading to the arrest and conviction of whomever left a mix of food containing toxins for 23 show horses at a Rancho Santa Fe ranch has been upped to $12,500, officials with the Humane Society of the United States announced Tuesday.

The society added $2,500 to the $10,000 already being offered by Rockridge Farm owners Bill and Debbie Tomin, who run the 10-acre boarding and training facility that houses about 30 American Saddlebreds.

One of the animals sickened by the toxins, a 14-year-old gelding named Forever Aptor, remains hospitalized, but veterinarians said he is making progress and may be released Thursday, Debbie Tomin said.

"He's finally getting better today," she said.

Someone came onto the property last week and fed the animals oleander leaves mixed with cut-up apples and carrots. Two pregnant mares were among the animals fed the toxic leaves.

Oleander is one of the most toxic substances horses can ingest and can cause cardiac arrest if not treated promptly. Symptoms include sweating, pawing and stomach pain, Tomin said.

When workers went into the barn Thursday morning about 6 a.m. they found one of the horses already down.

Three had to be rushed to an equine hospital in Bonsall, and all required testing to see if their hearts were damaged.

All of the horses except Forever Aptor have recovered, and blood tests that came back Tuesday showed that none suffered any heart damage, Tomin said. The pregnant mares and their unborn foals, due in February, do not appear to have suffered any damage, she said.

The Humane Society of the United States decided to add to the reward offered in the case because of the nature of the crime.

"The apparent deliberateness of this heinous act against more than two dozen vulnerable animals is disturbing," Jennifer Fearing, senior state director of the organization, said in a statement. "Those who abuse animals can be dangerous to people, and Americans have no tolerance for violence against the creatures who share our world."

Tomin said that there are still no suspects in the poisoning and that she and her husband have no idea why someone would do such a thing. They are installing a sophisticated security system in the ranch, which they've owned for 30 years.

"I want to be able to sleep at night," Tomin said.

Sheriff's deputies are investigating the case and asked anyone with information to call Crime Stoppers at (888) 580-8477.

Tomin has also set up an e-mail address – rsfsickhorses@gmail.com – for anyone who would like to send her information.