Transcript for Amanda Knox's Ex-Boyfriend Maintains Innocence in Book
Let's go and let's begin with the new book from amanda knox's former boyfriend, raffaele sollecito. He reveals new details of that night before that landed them in prison. Sollecito is now in the u.S., to promote his new book. For the first time, we hear the back story about sollecito's budding romance with amanda knox. And what he describes as their strange behavior in the days after knox's roommate was brutally murdered. Their torrid love affair, the fight of the gruesome murder. It's all detailed in raffaele sollecito's new tell-all book, "honor bound: My journey to hell and back with amanda knox." He describes it how the two undergraduates first met in october of 2007. He met knox at a classical music concert, just one week before knox's 21-year-old roommate meredith kercher's death. The couple were inseparable, until they were arrested and ultimately convicted for kercher's death. A month after they were released, sollecito opened up on italian tv, about the night kercher was killed. Paradoxically, he said, for me, that night was a beautiful night, because I spent the evening in amanda's company. We were living an idyllic love story. He goes on to write about his first night in prison, where he felt both great waves of indignation and a nagging sense of guilt. While he maintains his innocence, he admits that he and knox behaved oddly after the murder, in this unforgettable and to some, scandalous scene. He revealed he was angry at himself for having a foggy memory of the night of the killing because he and knox had smoked marijuana. Sollecito also acknowledged they had no real alibi the night of NOVEMBER 1st, EXCEPT FOR EACH Other. But then, in october 2011, after spending four years in what sollecito calls hell, he writes he felt indescribable joy when they were finally acquitted. What's important for me to say is thank you to everyone. Reporter: In a private moment in the basement of the courthouse, with knox, sollecito squeezed his hand. They hold something in common that very few people have ever had to deal with. Reporter: Knox is also writing a book, due out next spring. Her deal with harper collins is reportedly worth $4 million. Linsey, thanks.
This transcript has been automatically generated and may not be 100% accurate.