She Asked for It(1937)

Dwight Stanford and his wife, Penny, are a pair of spendthrifts who can't hold on to money, dependent for support on Dwight's rich uncle, who sends them a monthly allowance. Conrad Norris, Dwight's cousin, disapproves of Dwight and Penny, and resents his uncle's generosity. The uncle is the victim of a hit-and-run accident and, there being no will, Conrad, as next of kin, inherits. Switch, the uncle's lawyer, tells Dwight he is shutout with no hope of appeal. Dwight starts writing mystery novels about a fictional detective named Steven Knight, which become instant hits and the money pours in.