Vincent was obviously aware of their real identities since Lola described their appearance already. Although they weren't wearing proper magician clothes and looked like beggars, the description of his seniors matches them.
In addition, after he used his Item Sense ability, he already sensed the emblem that they have referring to their identities as the Tower Lord's disciples.
However, he wasn't really sure whether these people have become part of the Black Magic Organization already.
After all, Jairo, the fifth disciple that he captured is part of the organization… Speaking of which, this person is still imprisoned serving his life sentence… He was previously planning to send him to Ignacy but because of the recent events, he had already forgotten about him.
'My Mana Distortion wasn't too effective against them… It can only disrupt their Magic Tools' activation and their Mana Protection… I should try something else…' Vincent thought as he pulled out his cane…