Keystone cops were constantly chasing lawbreakers who they never caught

The Keystone Cops (often spelled "Keystone Kops") were fictional incompetent policemen, featured in silent film comedies in the early 20th century. The movies were produced by Mack Sennett for his Keystone Film Company between 1912 and 1917. source

First commercial sound film was The Jazz Singer, released in October 1927 source

Police shift focus to foreign tourists in Koh Tao murder probe   Thai VISA Forum

To protect and self-serve  Bangkok Post

3 sought for Koh Tao murders   Bangkok Post