to have seen her/it
He must have seen her.
He might have seen her.
Mi ricordo di averla vista prima.
I remember seeing it before.
He might not have seen it.
Sapevo di averla vista da qualche parte.
I knew I'd seen her somewhere.
— Goksung - La presenza del diavolo (2016)
Un vicino ricorda di averla vista giocare da sola fuori casa sua.
A neighbor remembers seeing her playing alone outside her house.
— Un affare di famiglia (2018)
He may have seen her.
He must have seen her.