Here is how the US courts deal with the presumption of innocence:
A presumption of innocence means that any defendant in a criminal trial is assumed to be innocent until they have been proven guilty. As such, a prosecutor is required to prove beyond a reasonable doubt that the person committed the crime if that person is to be convicted.
presumption of innocence | Wex | US Law - Law.Cornell.Edu
How does the state prosecution overcome the presumption of innocence of a criminal defendant?
Once the trial begins, however, the presumption of innocence becomes a “rebuttable” presumption, meaning that the prosecution can overcome the presumption by introducing evidence at trial tending to show that the defendant is indeed guilty of the alleged crime.
So the prosecutor must introduce evidence that the defendant is guilty of the crime, and while doing so, they are allowed to state that they believe him to be GUILTY, thus that is why they are offering the evidence to the jury.
Hi Katy
The key point in your post is that the accused has been charged, and thus the matter is before the Courts.
That is a key constitutional idea. The state accuses a person, via the process of charging, but a person cannot be deprived of their liberty, or convicted, without judicial oversight and the presumption of innocence applies. Such person must be brought before the Court expeditiously. Especially the case against the accused must be disclosed (discovery).
What we are talking about here is where a person has not been charged and maybe not even arrested
In general the state does not accuse people of crimes pre-charge.
Otherwise, as happens in countries with weak rule of law, an unscrupulous sheriff could accuse our dear Katy of crimes in the media, but keep the evidence secret, and you don't have access to the Court to clear your name.