In December 1939, Cooke entered Martin’s office and argued over the missing money from certain junkyards and so in a pure gangster style Martin grabbed a gun from under his table and pointed it towards Cooke, who in turn began to run and received one bullet in the back. Later he went to the hospital alone and after several days, for unknown complication on the wound, Ruby's close associate Leon Cooke died at the age of 28.

In January 1940, Martin was subsequently acquitted on the ground of self-defense