My thoughts, after watching some dateline and observing other cases similar to this, we are looking at an intentional act with malicious intent. For example, John Gardner is a model perp for a crime such as this.
http://abcnews.go.com/GMA/killer-john-gardner-lured-amber-dubois-threat-knife/story?id=10664589
People who do this are repetitive in nature and display psychopathic tendencies, but aren't necessarily psychotic. Rather they are normal, with some sort of dysfunctional way of dealing with things and anger problems. They can blend into surroundings and get away with things based on the randomness and obsurdity of the act.
Judging by our best evidence yet, the bike, the guy knows what he is doing. Whiskey Bay indicates we are dealing with someone familiar with their surroundings. The crime scene speaks volumes as well. He was smart enough to do it in a dark place with not many people around and about, unlike most other places in Lafayette, even at that hour.