Dun Da dun dun ~ Walter Schumann‘s ominous, four-note introduction to the TV show Dragnet was recognized by most Americans in the 1950s to signify “danger ahead.”

Dragnet was an American television series, based on the radio series of the same name, both created by  Jack Webb.

Webb played the Los Angeles police detective Sergeant Joe Friday. Ben Alexander co-starred as Friday’s partner, Officer Frank Smith.

The police term Dragnet describes coordinated measures for apprehending suspects, including road barricades and traffic stops, DNA tests, and general increased police alertness. The term is derived from dragging a fishing net across the bottom or through a promising area of open water.