Not quite free at amazon.ca (CDN$ 1.03
http://www.amazon.ca/Trace-ebook/dp/B00E50OKNO )
However, Warren Murphy co-authored
Created, the Destroyer which is free at both amazon.ca (
http://www.amazon.ca/Created-Destroy.../dp/B00AJWEYYW) and amazon.com (
http://www.amazon.com/Created-The-De.../dp/B00AJWEYYW)