|Season 1, Episode 9|
|Air date||15 April 2005|
Sniper attacks are occurring across L.A., but are all the shootings the result of one scattershot marksman or is a fad of sniper killings infecting L.A.? The team need expert assistance in trying to figure that out, and Charlie's theoretical models won't cut it.
A play on the concept of 'patient zero', the origin point of an infectious outbreak, whose identification and quarantine is often vital to the containment of a given condition. Here, Charlie attempts to develop comparable tracking algorithms.