A suspect starts out presumed innocent. The police (or investigating judge in those jurisdictions that have them) question the suspect and undertake whatever investigations are necessary to try to find evidence against the suspect. During the investigation the suspect is still, in legal terms, innocent. If the investigation officers ascertain sufficient evidence, the matter proceeds to trial, and the suspect then becomes the accused or defendant, and is still presumed innocent. S/he remains so throughout the trial until a verdict is reached.
At no time in this entire procedure - from first being considered a suspect up until the end of the trial - does this person ever lose the presumption of innocence, or ever required to "prove their innocence." The onus is on the police to produce the evidence, then on the prosecution to use this evidence to prove guilt.
Albertini seems to want to argue that the suspect loses the presumption of innocence during the investigative phase, but somehow regains it during a trial. This is not so, and it has been pointed out to him by a real, practicing legal professional, but Albertini thinks he knows better ....