M. Cooney, haven't seen the article, but some truth there. Most of Billy's killing was connected in some way with the Lincoln County War, its participants, events leading up to it and later consequences. Involved legal and court actions about mis-appropriation and embezzlement of money and property preceeded and continued during the War. These cases were never settled. Clearly the result of entrepreneural buccaneering. The territorial governor, General Lew Wallace (author of Ben Hur) ducked his responsibilities and kept working for a more rewarding posting.
If you are really interested, try to borrow Keleher's "Lincoln County War." It is a detailed account, with quotes from court papers, newspapers (taking sides), officials and participants. Billy's letter to Lew Wallace offers insight into Billy's mind. Psychopathic killer? I can't make up my mind. He had many friends.