This is an excellent interview about this case with Mary Ellen O'Toole, one of the pioneers of criminal profiling. Some of the questions aren't developed well by the interviewer (i.e. the pacemaker) but her analysis and profile are pretty compelling. JMO.
Source - WAVY TV10 News
In this interview, O'Toole says the victim was targetted.
But how do we know that? She might be correct, but I believe that is an assumption not currently confirmed by LE.