Thanks for sharing such a delicate topic.
This is the best steps an honest person would take, not only for the benefit of the company/employer but for consciousness sake.
However, in my own setting it might be very risky to take such steps. If the colleague has a toxic criminal attitude, your life might be at stake, neither the employer nor the authorities (police) can guarantee your safety should you run into troubles afterward.
Several assassination cases have been linked to this in the past. In such situation I'll really tread with caution while making sure that my report is backed by solid evidence. Depending on the amount or monetary value involved, I'll request for an oligatory withness protection measures from a legal entity.
!PIMP
RE: Cornering a colleague, aiming for the Greater Good