Calling All Cars was a radio police drama that featured dramatizations of true crime stories, depicting how each crime was solved and justice served. Episodes were mainly introduced by officers from the Los Angeles Police Department, with Sgt. Jesse Rosenquist, a police dispatcher, as a part of the entire run of the series. The show focused on the tedious routine of tracking down killers and robbers and was described as a crude forerunner of the popular police procedural show, Dragnet.

The show was broadcast from November 29, 1933, to September 8, 1939, and originally aired on the West Coast's Columbia Broadcasting System (CBS) and on the Mutual-Don Lee Network. It was sponsored by the Rio Grande Oil Company, which was part of the Sinclair Oil Corporation. The show only ran in areas where Rio Grande "Cracked" gasoline was sold. Calling All Cars was written and directed by William N. Robson and gained recognition in 1938 when it received the Institute of Audible Arts Trophy for the most consistently excellent program broadcast in the western United States during that year.

Sources: archive.org, wikipedia.org, otrcat.com