Grinder, please, no offense, but I believe there is a mix-up here between "suspect" and "arrestable person". It's an operational definition.
A person brought into an interrogation room for a high-pressure interrogation means that person is a suspect. The police may believe that they do not have enough credible information against the person to arrest them. That's why they are resorting to the high-pressure interrogation.
Once the police get the person being interrogated to sign some paper with an incriminating statement, whether true or false, the police incorporate that statement into the "reasonable suspicion" (which is the phrase naming the official details explaining why the person should be arrested, and may or may not be truly reasonable). The police do this to make sure that the court will accept the arrest. This makes an especially important difference in Italy, because for a crime with a long sentence, such as murder, the police and prosecutor get to have the person arrested imprisoned for one year before the trial even starts.
What I am trying to say here is that Raffaele and Amanda were effectively in custody when each entered their respective interrogation rooms.
They (certainly Amanda) had become suspects in the minds of the police and prosecution from Nov. 2 or Nov. 3, 2007, based on Mignini's public comments on staging of the break-in (which I know only through hearsay) and the requisite time to organize the overnight interrogation of Nov. 5/6, 2007.
Here are excerpts from Brusco v France 1466/07 (Google Translated):
45. The Court also recalls that the person held in custody has the right to be assisted by a lawyer from the beginning of this measure and during interrogation, and even more so when it has not been informed by the authorities of his right to remain silent (see the principles established in particular in cases Salduz v. Turkey [GC], no 36391/02, §§ 50-62, 27 November 2008, Dayanan v. Turkey, No. 7377/03 , §§ 30-34, 13 October 2009, Boz v. Turkey, No. 2039/04, §§ 33-36, 9 February 2010, and Adamkiewicz v. Poland, No. 54729/00 §§ 82-92, March 2, 2010 ).
47....The argument that the applicant was heard as a witness is irrelevant, as purely formal, since the judicial and police authorities had kind as to suspect him of involvement in the offense.
{Emphasis added.}