Amanda Knox "was reading Harry Potter when Meredith was murdered", she claims in her memoir.
Ms Knox also imagined committing suicide in prison, she has said, in a long-awaited memoir that claims she was smoking marijuana and reading Harry Potter when her British roommate was murdered.
The 25-year-old American, who spent four years in an Italian jail for the killing of Meredith Kercher, also insisted it was not true that she performed cartwheels at a police station the day after the murder.
She also claims she was sexually harassed by prison guards.
Ms Knox, who was released in October 2011 but faces a retrial, said she hoped to "set the record straight" with 'Waiting To Be Heard', for which she is said to have been paid $4m (€3m).
"Now that I am free, I've finally found myself in a position to respond to everyone's questions," she writes in the book, which is scheduled to be released in the US later this month.
"Until now I have personally never contributed to any public discussion of the case or of what happened to me. This memoir is about setting the record straight."
In a copy obtained by 'The New York Times', she gave her most detailed alibi so far for the night in November 2007 when Ms Kercher had her throat cut in her room at their shared house in Perugia.
Ms Knox reiterated that she was with her then- boyfriend, Raffaele Sollecito at his flat, claiming that the pair were smoking joints, watching the film 'Amelie' and reading a German translation of Harry Potter.
"Around our house, marijuana was as common as pasta," she wrote.
Mr Sollecito, now 29, was eventually convicted of Ms Kercher's murder alongside his girlfriend, based on DNA evidence that their lawyers dismissed as feeble. After being released he moved to Switzerland.
While conceding that she naively followed the directions of Italian police "like a lost, pathetic child", Ms Knox insisted in her book that her actions after becoming a suspect in the murder had been exaggerated.
After being photographed kissing Mr Sollecito, it was widely reported that she had cartwheeled in front of police. Instead, she claimed, she nervously paced a corridor, tired from a lack of sleep.
"First I showed not enough emotion; then I showed too much," she wrote.
"It's as if any goodwill others had toward me was seeping out like a slow leak from a tire, without my even realising it."
She said that she had regretted writing a diary entry in which she darkly joked that she could "kill for a pizza".
"The words in my journal were taken literally, and they damned me," she said. "It was a situation I would find myself in again and again.
"When Meredith was murdered and I was arrested, it was so shocking. It was paralysing. Everything toppled."
In the 463-page book, she also criticised her treatment at the hands of Italian guards. When she asked to make a phone call they "looked at me like I'd asked for caviar and Prosecco", she wrote.
According to the memoir, the police interrogated her for hours and would slap her on the back of her head.
Ms Knox makes the claims in spite of the fact that the Italian police are taking legal action against her parents for making similar allegations.
Having been jailed, she wrote, she practiced Italian and read authors such as Dostoyevsky and at one stage "imagined committing suicide by suffocating myself with a garbage bag".
In the memoir, she also details how she thought of killing herself by swallowing shards of glass.
Ms Knox describes in the book how she wrote her mother a letter just before she was released from prison, anticipating that she might not get out. However, she arrived back in Seattle before her note did.
Ms Knox, who is expected to be tried in absentia next year, said in the book that she had found it difficult to adjust to how quickly the outside world had changed during her time in prison.
"I hadn't picked up a cell phone in years, and never a touch screen," she wrote. "This device was as good as sci-fi to me."
Since returning to the US in 2011, Ms Knox has largely avoided the spotlight and is mostly left alone in her hometown.
Now studying at the University of Washington, she enjoys rock climbing, hiking, camping and other outdoor activities.
But, she says, she is still dealing with difficult emotions.
"Things creep up on me and all of a sudden I'm overwhelmed by the feeling of helplessness and that desperation and fear to even hope," Ms Knox said.
"Just that can make my heart race and makes me paralysed until I can breathe it away." (© Daily Telegraph, London)