The Deadly Dove, by Rufus King (epub/Kindle/pdf)
With greedy anticipation, Alan Admont listened to gangster Joe Inbrun plan murder. The Deadly Dove, a ruthless killer, would be hired. The Dove worked quietly and swiftly. The result would be a fatal accident or illness. Alan had just married wealthy and eccentric Christine Belder, who was old enough to be his mother. It was a pleasant setup for Alan -- until Joe Inbrun saw in it a way to collect an old debt. Then suddenly Christine cut Alan out of her will and Alan now had to try desperately to keep her alive. But the Dove was at work. Not even Joe could stop him. Alan waited in terror for the deadly blow that would leave him penniless when without warning murder struck in the Belder mansion. But the victim was not Christine...