To add to the above post (#2818), I should mention we also know that Knox was a suspect from the beginning of the impugned interrogation based on Sollecito's account of his interrogation, which started prior to Knox's. The interrogators pressured Sollecito to abandon his alibi supporting Knox. Unfortunately, the Italian police violated Italian procedural law and left no documentation of the questions and answers during Sollecito's interrogation.
As discussed previously here, the ECHR in its judgment Knox v. Italy examined the issue of whether or not Knox was a suspect during the two episodes of questioning that resulted in two statements on 6 November 2007 - the one first before the police (1:45 am statement) and the second before the prosecutor (5:45 am statement). In paragraphs 147 through 152, the ECHR judgment discusses this issue. In paragraph 151, the reasons why the ECHR believes that Knox may have been a suspect (even though claimed to be a witness by the authorities) during the first interrogation are listed (Google translation):
It seems to me that the ECHR decided not to conclusively hold that Knox was a suspect during the first interrogation because from a human right viewpoint, the actions of the interpreter were so unfair to the outcome of the trial that it was unnecessary. The ECHR instead in paragraph 152 focused the denial of a defense lawyer claim to the second interrogation, because the Italian courts (CSC) itself stated that contrary to Italian law, Knox had been denied a lawyer during that interrogation even though she had clearly become a suspect with her first (1:45 am) statement:
The ECHR then, in paragraph 153, acknowledges that the Italian courts had stated that both of Knox's statements could be used against her only for the alleged crime of calunnia against Lumumba:
Finally, the ECHR concludes that the Italian Government has not justified use of the impugned statements, made without a lawyer, as evidence against Knox in any way that is valid under ECHR case law. Therefore, there was a violation of Convention Article 6.1 with 6.3c:
See:
https://hudoc.echr.coe.int/eng?i=001-189422