MEXICO CITY – It is tough coping with the violent killing of a family member. It's probably even harder to imagine that person being murdered by a pack of wild dogs.
Many residents of Mexico's capital are rejecting the theory of prosecutors that stray dogs killed as many as five people in recent weeks at a hilltop park in the middle of one of the world's biggest cities.
It is easier for victims' relatives like Ana Maria Martinez to believe crazed killers tortured and murdered her brother, Samuel Suriel Martinez Sanchez, 16, and left his body to be mauled by dogs.
Animal rights activists say the bunch of innocuous-looking strays rounded up so far are being framed. They plan a sit-down protest in front of Mexico City police headquarters Friday, even though authorities have pledged not to euthanize the dogs. Pressure from animal lovers forced the city to stop regular roundups of strays several years ago.
But animal experts said Thursday it is quite possible that those dogs, or others, did turn into killers, saying people have misconceptions about dog attacks. City prosecutors have said autopsies of four of the bodies concluded the deaths were caused by blood loss from the bites of around 10 dogs, inflicted before and after death.
The refusal to blame dogs for the deaths may stem from people's mistrust of often corrupt or incompetent prosecutors. Drug cartels regularly dump bodies of their victims in vacant lots, and authorities don't investigate most such cases.
"My brother was killed by human beings, whether they set the dogs on him before or after, we don't know," said Martinez. "I think it was a crazy person, or several, or maybe even satanical people for their rituals."
"There were dog bites, but dogs don't kill people," she said. "More than anything else, we want this cleared up, so that other innocent people don't have to go through the suffering we're going through."
It is an incredulity fed by the innocuous-looking faces of the 50 or so mutts rounded up at the Cerro de la Estrella park where the attacks occurred in December and early January. A few are about the size of a Labrador, but many are small or mid-sized dogs, including beagle and border-collie mixes.
Many look like the discarded pets they are. Residents near the 353-acre (143-hectare) park in the poor Iztapalapa neighborhood say people regularly drop off unwanted pets there, but say the dogs have never caused problems before.
"They rounded up a bunch of very innocent-looking dogs," said Martinez's father, Benigno Juan Martinez Martinez, a balloon vendor.
But Jim Crosby, a Florida-based former policeman who is an expert witness for canine aggression cases, said: "Dogs, singly or in groups, can easily kill a human being. I have seen some people ripped extremely badly apart by one or two dogs. People in the United States have been killed by everything from Presa Canarios (a large breed) ... to Pomeranians."
Moises Heiblum, professor of animal behavior at the school of veterinary medicine at the National Autonomous University of Mexico, said feral dogs as individuals "probably could not carry out a ferocious attack of this type" and normally avoid human contact.
But the dynamics change when a pack is formed, Heiblum said. "When a group comes together, they are capable of an extremely intense and even fatal attack. That is possible."
Animal control warden Armando Garcia, who was patrolling with an assault rifle this week, said there was no question that strays had formed a pack in at least one part of the park.
"You can tell when there's a pack: There's an alpha dog and his followers, and they've marked out territory and they challenge you when you enter it, with growls and barking," Garcia said.
Doubts about the official theory are passing among neighbors whose homes, some just wooden shacks, front the park. Some say nobody heard anything on the nights of the killings, and surely the dogs and their victims would have made noise. Others note the dog bites were found on the bodies' arms and legs, and not the throats.
Experts say it is a popular myth that wild animals attack the throat. They say dogs generally bite people wherever they can reach, often the arms, legs or buttocks.
"If they're in a pack, they're probably grabbing whatever is closest to them," said Dr. Julie Albright, who holds the PetSafe Chair in Small Animal Behavior Research at the University of Tennessee College of Veterinary Medicine.
One resident, former policewoman Magali Flores Guzman, questioned how dogs could have been responsible when people regularly walk through the park without incident.
But Albright said the victims' behaviors could have triggered an attack. "Something drew them over there," she said. "Maybe food drew them there."
A relative said two of the victims had just bought food before entering the park.
Some residents said another victim may have been drunk or passed out after drinking with friends in the park. Albright said dogs may be more likely to go after people who are stumbling or unsteady on their feet.
The experts said trying to run away from a dog pack can also trigger an attack. They counseled standing still and slowing retreating backward, while avoiding eye contact.
The Associated Press contributed to this report.