The following sentence is from a book. The context is the main characters just finished fighting some monsters. One character looks distracted, and when one of the others asks her if there's something wrong, she says:
いえね、さっきの化け物が単独。もしくは、ハグレなら問題はないのだけれど。
Since there is no kanji with ハグレ, I'm having problems trying to figure out what they're talking about. Does anyone have an idea based on context? I guessed maybe the word 逸れる, but I'm not sure it makes sense here. Thanks.