American Sniper is based on the memoirs of Navy SEAL Chris Kyle, Scott McEwen and written by Jim DeFelice. Navy SEAL Chris Kyle is the deadliest shooter of all time, and is called by his enemies as "the devil." From 1999 to 2009 he set a record with the most murders as a sniper in the history of the US Army. Kyle learned the tricks of the trade already when he was a child and would play a prominent role in the fight against terrorism that began after 9/11.