(Fairfax County police)

The horses, which are part of a Herndon equestrian program for people with disabilities, were slashed between 9 p.m. Wednesday and 9:30 a.m. Thursday after the animals were put in paddocks for the night, Fairfax police said. The paddock where the horses are kept is in the 2600 block of Centreville Road next to Frying Pan Park.

A volunteer with the Spirit Open Equestrian Program discovered that the horses had been cut when he came in to feed them Thursday morning, said Julia Kelmers, another volunteer with the program.

A veterinarian who treated the horses said the wounds were fresh, so it was more likely that the horses were attacked Thursday morning, Kelmers said. It appeared that the animals had been cut with a knife or other sharp object, Kelmers said. A photo of one of the horses shows a long, deep gash on its side. (The photos were too graphic to include with this post.)

(Fairfax County police)

Spirit’s Facebook page says Tess, who is described as a “gentle giant mare,” may have fought back against the attacker

Kelmers said nothing was taken from the barn in the incident.

Police have no motive or suspects in the attacks, but a man was spotted stumbling in Frying Pan Park about 11 a.m. Thursday morning. It is not known whether he was involved in the incident. He is described as a white man about 5’8” tall and 160 pounds.

“[The paddocks] are near a trail where a lot of local people go running. We’re hoping someone was on the trail and saw something,” said Officer Shelley Broderick, a spokeswoman for the Fairfax County police.

A security guard has been hired and the husband of the group’s founder, Davorka Suvak, spent last night at the stable to ensure that nothing else happened to the horses.

Spirit, a nonprofit organization founded in 2007, provides riding opportunities for people with physical, emotional and cognitive disabilities and diseases. Most of the people in the program are children, Kelmers said.

“It seems really strange and hard to process,” Kelmers said of the attack. “It’s also really sad. I know how much the horses mean to these kids.”

(Fairfax County police)

A photo caption in this story originally incorrectly described a volunteer as holding the reins of one horse; he is holding a lead line.