Herman Capshaw was a former marksman for the Marines and construction worker who kidnapped a boy, Justin Lafferty, in 1993 and raised him as if he were his own. He then programmed Justin to be his "soldier" and kill for him.
History
In 2003, Justin committed a string of random killings on Mott Street in order to hide the murder of Capshaw's boss, Charlie Rodriguez. Capshaw was initially charged with these murders until Justin confessed to it all. Capshaw is currently serving a life sentence for the kidnapping and four counts of first-degree reckless endangerment, whilst Justin was acquitted and sent to a psychiatric facility for treatment. (L&O: "Sheltered")
He is likely based on "DC sniper" John Muhammed.