ST. LOUIS — The investigation continues to find out who is responsible for the three dogs that killed a St. Louis man and injured two others this week.

Kristen Duhr, canine behavior specialist, has spent the past 20 years rehabilitating aggressive or unruly dogs.

“It’s the result, basically, of poor upbringing,” Duhr said.

“Under socialization, separating puppies from their mothers too early and raising dogs in an aggressive environment eventually leads them to threaten or attack strangers,” Duhr said.

In this case, all three dogs were pit bull terriers.

“I’ve seen Chihuahuas be just as unfriendly,” Duhr said. “It’s not a race situation.”

If you come face to face with an aggressive dog, don’t run.

“The best thing you can do is recognize that running will encourage a dog to hunt,” Duhr said. “If you have one dog that does it, you’ll have two more hot on its heels. What you should do is turn around the other way and slowly walk away. If you have anything on you like food, Hansel and Gretel follow it to keep the dogs as busy as possible.

She also recommends dog mass.

She said there is a cure for aggressive dogs: socialize them early and give them plenty of attention. Duhr said aggressive dogs are the result of owner neglect.

Rehabilitating a dog that is overly aggressive or that has attacked someone is incredibly difficult. Most scenarios end with the dog being put down.

The dogs in this case were taken from a residence, according to a spokesperson for the Department of Health, which oversees animal control. The ministry released a statement today.

“Three dogs have been seized and are being impounded at our shelter as part of the investigation into this incident. Our Animal Care and Control Officer is investigating. Service requests are not created based on the breed of a dog A review of all animal-related calls through the Citizens’ Service Bureau (CSB) revealed very few requests for service in this immediate area.In an eight-block square of the 4800 block of San Francisco, our data shows only two service requests in the past year, one for a leash law issue and the other for an animal bite report. St. Louis, there have been 1,617 service requests for all breeds of dogs (service request only, request not confirmed) for strays/dogs on the loose/leash law/dangerous dogs in town. residents to report any concerns to CSB at 314-622-4800.”