The Alfred Hitchcock Hour: Memo from Purgatory (1964)

Synopsis
For this episode, host Alfred Hitchcock pointedly dispenses with his traditionally humorous prologue and epilogue, explaining that the subject matter is far too serious for any such jocularity. Adapted by Harlan Ellison from his own semi-autobiographical 1961 book Memos from Purgatory, the episode stars an up-and-coming James Caan as the Ellison counterpart, here named Jay Shaw. In order to research a book about juvenile delinquency, Shaw goes undercover and becomes a member of The Barons, a vicious Brooklyn street gang headed by a psychotic youth named Tiger (played by a decidedly pre-Star Trek Walter Koenig). Quickly ingratiating himself with the mercurial Tiger, Shaw earns the distrust of the rest of the gang, who ultimately manage to blow his cover. The result is explosive, violent, and tragic -- and as is often the case in such matters, the principal casualty is the one who is least responsible for the situation. ~ Hal Erickson, All Movie Guide