CHICAGO (WLS) -- A Lincoln Park dog owner is shaken after a violent encounter Monday afternoon.Sammie, a 2-year-old Border Collie-Labrador mix, is recovering from her wounds, which required several stitches."Heartbreaking. Awful. It was, it crushed me all day," said Sammie's owner, Michelle Praxmarer.Praxmarer was walking Sammie in the 400 block of West Deming Place, a popular stretch for neighborhood dog walkers who are headed to the lake. She said she and Sammie passed by two men who seemed distressed to be holding onto the leash of a hyper Pitbull-type dog.Moments after passing the erratic animal, Praxmarer said it broke free."All of a sudden I just see this dog running full speed right to her and latched right onto her and just started attacking," she said. "It was so crazy. I was frantic. I didn't know what to do because I myself didn't want to get bit."Praxmarer eventually managed to separate the dogs and immediately took Sammie to a vet. Fortunately she did not sustain any internal injuries.ABC7 Eyewitness News was not able to reach the owner of the other dog Tuesday, but multiple neighbors and dog walkers said that the dog has been aggressive in the past."I'm just really worried about the other dogs in the area and their safety, as well as small children," Praxmarer said.