The Bitter Bite — Jeffrey Ashford

When Penny Hurst is raped by one of the workmen at her parents' London home, the police investigation dead-ends quickly upon the suspect's seemingly rock-solid alibi. Though everything circumstantial points to his guilt, there is no real proof, and the police are grudgingly forced to admit defeat.
Penny's boyfriend, Calvin Slade, cannot let the man get away so easily. At first, Calvin's reaction seems to be to withdraw from Penny, even refusing to visit her. But soon it becomes clear that he can't suppress an overwhelming impulse toward revenge. With the help of a friend, Tim Rees, who has been supporting Penny all along, Calvin devises a plan to force the workman to confess to the crime.
When their confrontation with the suspect turns violent, Calvin and Tim must deal with the consequences of their own actions, regardless of how innocent or justifiable their intentions may have been.