I think you mean uninvolved, and Knox made that statement only after 36 hours of intense interrogation by the police.
However, her initial statement was that she spent the entire night with her boyfriend (for the first time). He was being interviewed at the same time and said she did not spend the night with him.
Yes, they both said they were at his place at first. When she was confronted with phone records that showed that wasn’t true she changed her story. She lied about texting her boss and when she was confronted with proof that she did text him, she said she was there when the boss raped and killed Meredith.