Speaking to The Times, June Steenkamp said she and her husband, Barry are haunted by the images of their daughter's shooting saying: "Her terror and helplessness. Her yells for help, piercing the silent night air."
According to June, Reeva had confided that she, "had not slept" with the runner as she was, "scared to take the relationship to that level".
"Her clothes were packed. There is no doubt in our minds, she had decided to leave Oscar that night," wrote June in her book, Reeva: a Mother's Story, serialised in The Times.
June has described Pistorius as "arrogant", "moody", "volatile" and "combustible", and a "trigger-happy" gun fanatic who was also "possessive" of her daughter.
"It was Reeva's bad luck that she met him, because sooner or later he would have killed someone. You can laugh about some things. It's not like you are miserable all the time. It's just this wrenching pain that you get in your heart. It's always there. The minute your eyes open in the morning, or if you wake up in the middle of the night, there it is," said June.
The proceeds from her book will be used to help with the family's present financial troubles.
June is also planning on using some of the funds to start a fundraising campaign to establish a foundation for female abuse victims in South Africa.