The American woman accused of murdering British student Meredith Kercher in Italy said she acted "like a lost, pathetic child" during the investigation and wants to "set the record straight", it was reported.
Amanda Knox also claimed she was sexually harassed by prison guards and considered suicide, according to the New York Times.
Writing in her memoir Waiting to Be Heard, she wrote: "Until now I have personally never contributed to any public discussion of the case or of what happened to me.
"Now that I am free, I've finally found myself in a position to respond to everyone's questions.
"This memoir is about setting the record straight."
According to the memoir, the police interrogated her for hours and would slap her on the back of her head.
Miss Knox made the claims in spite of the fact that the Italian police are taking legal action against her parents for making similar allegations.
She also claimed to have been reading a Harry Potter book, smoking marijuana and watching a film at her boyfriend's flat on the night of the murder, saying that "around our house, marijuana was as common as pasta".
Last month Italy's highest criminal court overturned her acquittal for the murder of Miss Kercher, from Coulsdon, Surrey, in November 2007.
The American returned home to Seattle after she was dramatically cleared following four years in jail in 2011 but now faces the prospect of returning to the country for a new trial.
In the memoir she went on: "First I showed not enough emotion; then I showed too much".
Miss Knox added: "The words in my journal were taken literally, and they damned me", she wrote.
"It was a situation I would find myself in again and again."