as bednobs says, 'paedophile' means a huge range of things - technically a 16-year-old who has sex with a 15-year-old is one, though I doubt any of those are ever prosecuted. It may be that you could find out the details of the offence, but why bother. You had a normal commercial relationship with him, he cheated you, there are remedies, you have instigated one. It never pays to get too het up about other people's wickedness, it starts to eat into your own life, and what have you done to deserve that? Treat him like any other thief.
If you saw him again, you could tell him you know about his past, which would put the fear of god into him. But don't start kicking him for crimes he's committed against other people; the state has already dealt with that on your behalf.