English Translation
Not only my daughter but some of her classmates say that they saw the criminal.
i really don’t understand “virent” here
Hello @Mateo-Piestro,
I can see why, it’s just one of those sentences… 
When I first read the French sentence, I thought maybe they meant “virer” as in to expel the criminal from school/college.
Only after reading the English translation, did I understand what’s going on here.
The verb “virer” can be translated many different ways, depending on context.
When talking about people, “virer” usually means to fire (from work) or to expel, as could be the case here for instance (although the sentence would still sound weird to me).
In this case however, “virent” is not the verb “virer”, it is the verb “voir” (to see), in the simple past tense (passé simple).
So technically, the English translation “…that they saw” is correct.
In spoken French, I’d say “Non seulement ma fille mais certains de ses camarades de classe disent qu’ils ont vu le criminel”.
Generally speaking, the simple past tense is rarely used in French, especially when speaking.