A pack of dogs have been killing animals in Washington state. The article quotes one sheriff who speculates that "four or five" of the dogs are pets, and become wild/feral at night, joining up with the pack.
I found it interesting that this news item has generated over 2,000 comments. Stories of wild dogs all over the U.S. -- discarded "pets," animals that have not been spayed or neutered, dogs that are allowed to stay off leash and run free, all contributing factors to these packs.
Bloodthirsty pack of dogs take out 350-lb. llama - Yahoo! News