CBS News Correspondent Cynthia Bowers reports the dogs attacked at least two people Sunday in the Dan Ryan Woods forest preserve - seriously injuring one and killing another.
Cook County Forest Preserve District spokesman Steve Mayberry says the victims - both women - had been running through the woods when they were attacked.
Mayberry says officers are hoping someone with information about the dogs' owners would contact them. The dogs were not wearing tags.
"These dogs had no identifying features that would make it easy to identify their owners," says Mayberry. "We have two deceased dogs but no real way of identifying their owners, barring someone coming forward."
The woman who was killed - 48-year-old Anna Cieslewicz of Evergreen Park, Ill. - was a marathon runner, but not even she was able to outdistance the two pit bulls that brutally attacked and killed her.
"She ran in the woods, she ran in places that were dangerous and sort of knew that, but never thought anything could happen to her," says Sandi Barber, Cieslewicz's daughter.
Cieslewicz wasn't the only victim. Another woman, 46, whose name has not been released, was the first to be attacked and managed to make it to Christ Medical Center in nearby Oaklawn, where she alerted police. She was subsequently transferred to another hospital and is listed in serious condition.
Police investigating the first victim's report went to the forest where they then discovered Cieslewicz - fatally injured - and very nearly became victims themselves.
One policeman says he saw the dog coming at him and shot and killed him.
The second dog was spotted and killed a short distance away. The pit bulls looked about 2 years old and weighed 80 and 60 pounds respectively. And they appeared to have been well cared for. Adding to that theory, a portable doghouse, rug, and a freshly filled food bowl were found in the woods nearby.
With both of the dogs involved in these maulings now dead, police here think they've removed the immediate threat, but now comes the hard part: figuring out who owned the animals and how two such dangerous dogs wound up running wild in such a public place.