Twenty three-year-old Zehra and her mother Nabeela were shot dead in their home in Township area of Lahore by her father Shehzad Butt.
Zehra was the widow of Faizan Haider, one of the two men who were shot dead by Davis last year.
According to police official Tayyab Hammad, Zehra wanted to remarry but her father was opposed to the move as he feared that the compensation which the family had received from Davis might go to Zehra's new husband. Zehra's mother was in favour of her plans to remarry.
Butt fled from the house after shooting the two women, police said.
"There have been quarrels between Zehra and her father over the marriage issue. Nabeela would side with Zehra as she was of the view that Zehra was too young to be denied the right to a second marriage," Hammad said.
The CIA contractor claimed that he fired at them in self-defence when they tried to rob him while the families of the slain men insisted they were not robbers.
Police arrested Davis and he was put on trial in a district and sessions court.