BEVERLY HILLS, Calif. — Weeks before the 50th anniversary of President John F. Kennedy's assassination this fall, ReelzChannel will take another look at the killing in a docudrama that suggests a Secret Service agent fired one of the bullets that felled Kennedy.

"JFK: The Smoking Gun" is based on the work of retired Australian police Detective Colin McLaren and the book "Mortal Error: The Shot that Killed JFK" by Bonar Menninger.

McLaren spent four years combing through evidence from Kennedy's death on Nov. 22, 1963, in Dallas. He and Menninger also relied on ballistics evidence from an earlier book by Howard Donahue....