Mark Hennessy

Two beach combing-shutterbugs accidentally capture a murder on film. Now detectives, the boys set out to capture a murderess shot only from behind, with a rose tattoo on her behind. Fun in the sun turns dangerous when they end up shooting bullets instead of film. (imdb)

Steve Beck (Vince Martin) is a Karate instructor, Robby Mason (Tom Jennings) his prize student. Beck is using drugs to give him an edge. Guy Duncan (Craig Pearce) is Beck's drug connection that threatens to expose Beck as a user then Beck kills Duncan, but Robby was witness to this. Robby confronts Beck about the killing, during the karate championship. Beck tries to kill Robby during the match and again afterward in the street. (imdb)