The damage to the body “was so extensive that there was nothing left to compare bite marks to,” Jim Agnew, a Goochland County sheriff, said in a news conference.

After a woman in Virginia was mauled to death by her own dogs, her friends and family are now asking an important question: what could cause a dog to turn on its owner?

The 22-year-old woman, Bethany Lynn Stephens, was found dead in the woods with her two dogs apparently “guarding” her body.

Check it out per LiveScience:

Bite marks on the body confirmed that the dogs attacked Stephens, and Agnew also said he and the other officers observed the dogs eating Stephens’ body. Family and friends said Stephens had raised the dogs since they were puppies and that they were affectionate.

Experts say there’s no way to know for sure what caused this attack.

“It’s a difficult incident to understand. It certainly is horrible,” said Richard Polsky, an animal behavior and dog-bite expert in Los Angeles. “We just don’t have enough information to understand why these two dogs turned on this owner,” Polsky said.

But in general, for dogs to act aggressively, there needs to be some kind of external “trigger,” Polsky said. One possibility is that, while Stephens was walking the dogs, something out of the ordinary happened; for instance, the dogs sensed “prey,” like a rabbit or squirrel, and tried to go after it. If Stephens interfered with the dogs while they were going after prey, they may have redirected their aggression toward Stephens, Polsky said. “The dogs may have been thwarted in doing something, got frustrated and turned around and attacked the owner,” Polsky told Live Science.

Ron Berman, a dog-bite expert and certified forensic consultant, agreed that this could be a scenario in which dogs attack their owner. “Usually, you have some initial aggression, the human tries to stop the aggression, the dog reacts to that,” Berman told Live Science.

Berman added that it’s possible Stephens’ dogs were not fed well, because dogs don’t typically try to eat a human body after an attack, unless they haven’t been getting enough food.

Officials noted that lately, Stephens’ dogs had been living with her father, who kept the dogs in a kennel outside; and the animals had little human contact besides occasional visits from Stephens.

Rather than both dogs attacking Stephens at once, it’s more likely that one dog initiated the attack, and the other joined in, Polsky said. It’s also possible that the dogs had shown signs of hostility before, but these signs were overlooked, he said.

There are about 5 million dog-bite cases annually in the U.S., Polsky estimated. Around 30 to 40 people die each year from their injuries, and an estimated 100,000 are injured badly enough to require plastic surgery or extensive suturing, according to Polsky.

Most fatal dog attacks involve pit bulls. (Officials identified Stephens’ dogs as pit bulls.)

To help stop these deadly incidents from occurring, there are a few small tips you can put into practice. Dog experts recommend educating children not to run up to a dog they don’t know. Most attack victims are, in fact, children and caused by male dogs.

If you want to own a pit bull or a Rottweiler, definitely go to reputable breeder who has bred their dogs for docility rather than just looks.

Have you ever been attacked by a dog?