Harnett County Sheriff Larry Rollins calls the case malicious. He says investigators have identified four girls between the ages of 12 and 15 and are close to making arrests.
While investigators do not have a motive, Rollins said the girls likely used hairspray or perfume to start the fire.
"I haven't stopped crying since I've been home," said Hamilton, who owns
Dixie, Hamilton's 2-year-old registered spotted saddle horse, had just been sold for $4,500. Before the owners of Hamilton Stables could even send her off, authorities say someone tried to burn off her tail.
"I can't understand people like this," Hamilton said through tears.
Whoever committed the crime came on the Hamiltons' property while they were not at home. The family was away at the beach for a three-day weekend and did not know anything was wrong until they returned.
"I feel guilty because I went on vacation," Hamilton said. "If I'd been home, I would have heard the dogs bark and could have stopped this."
The horse's flowing tail once brushed the ground. Now, what is left of it may have to be amputated. Even worse, Dixie's veterinarian says she has only a 60 percent chance of surviving.
Hamilton , who also operates camps and provides horse-riding lessons, now spends about six hours each day tending to Dixie, who is on antibiotics and requires medicated baths -- which are very painful for the horse -- four times a day.
Even if the horse recovers, her life will never be the same. Without a tail, she cannot swat flies.
"Who's going to stand here 24/7 and swat flies for her?" asked Hamilton.
And without a tail, Dixie is unable to communicate with other horses and will not be able to spend much time outdoors.
"I want her to live because I love her, I've always loved her," Hamilton said.
The infection in her tail spread to her leg, making the horse, which has been known to come up to strangers, now struggle with every step.
Earlier this month in Lincoln County, animal control removed 28 horses from a farm. Authorities said the animals were starved when they found them. Several of those horses are now being nursed back to health in Apex.
The horses' owners, Ann MacCallum and Shane Schlageter, face dozens of charges of animal cruelty.