There were three people.
CHAIR-ah-no — 'c'erano' comes from 'esserci'; the 'c' of 'ci' merges with 'erano'.
Use when describing the number of people involved in an incident. The number of suspects affects the level of response and which unit is dispatched.
'C'erano' is the imperfect of 'c'è' — used for describing a past state or scene. The present 'ci sono' is for current situations.
Era solo uno/una.
There was only one person.
Singular — important distinction for police search.
Erano almeno cinque.
There were at least five.
'Almeno' (at least) signals uncertainty about the exact number.
Non riesco a dire quante persone fossero.
I can't say how many people there were.
Honest answer when you genuinely did not count.
In Italian police reports, witness proximity is always recorded. 'A circa dieci metri' (about ten metres away) affects how much weight your testimony carries, especially for face identification.