Wolves have a bond within the pack unlike anything humans have. While I have only heard of one wolf attack that happened in Minnesota last year, it doesn't surprise me that they hung around. They had just lost an important member of their pack. Up in this area, if bear dogs get too close to a den with pups, the pack usually ends up killing the dog or dogs. Usually happens during spring season or summer during training.
I have only only seen them singly or in pairs around here, and not close up on foot for the last 35 years.
Interestingly just now I went out to feed my wood boiler about 8pm our time and I startled a coyote. Being that close in to our house in this harsh of winter makes me concerned about our dogs, whom aren't that big. I will be packing a 357 or 22 WM when I let them out the rest of this winter, and I won't be able to let them out by themselves. He didn't move off more than 150 feet. I could still see his eye reflections in my headlamp light.