The Blind Side by Patricia Wentworth

Ross Craddock was just the type to be murdered. The new landlord of Craddock house, he begins by giving eviction notice to his aunt Lucy. He threatens the doorman with dismissal. He makes a violent and unwelcome pass to his cousin Mavis. He is vindictive and spiteful and ends up dead. The suspects include Lee who may have walked in her sleep and killed him out of unconscious fear. Or Peter who may have found Ross' advances to Mavis unbearable. Or aunt Lucy who unexpectedly came back. Or possibly Bobby who was still in love with Mavis and furious that she was seen with Ross. The answer is yet another Wentworth twist.