KEY WITNESS, based on Frank Kane's novel of the same name, is sort of the successor to MGM's 1955 BLACKBOARD JUNGLE, but with more acting flourishes (mostly by the supporting cast) and realistic settings. By 1960, delinquency and gang violence were recognized as an unpleasant reality outside of "old" urban centers such as New York -- but also not always (or often) involving such well-scrubbed suburbanites as those depicted in REBEL WITHOUT A CAUSE. Though its script stumbles in some notable places (a few involving basic logic -- except that this was a new world for many of the people who would have been watching in 1960), KEY WITNESS is a good depiction of the law abiding running up against the sociopathic lawless, with horrendous consequences for all concerned. The movie also plays, in somewhat naive fashion, on a racial angle in its plot and characterizations -- this is an odd touch, considering that the entire gang in Kane's book, if memory serves, was African-American. (Additionally, the book is more violent and also a lot more raunchy in terms of the Ruby character, who alludes to the idea of explaining her assault on the witness's wife because of a (rejected) lesbian overture in a courthouse ladies' room). The movie ends a little too squeaky clean and optimistically, not that differently from THE BLACKBOARD JUNGLE, but is more harrowing along the way. Along with releases such as THE SUBTERRANEANS, which was done around the same time, it was all a really interesting venture by MGM into territory far from its roots in high art and Americana, and an admission that the 1940s were long-gone. And anyone who likes the movie should check out the novel.