Is it ever okay to lie to a corrupt person in order to prevent them from committing a grave sin? Please view context below

Is it ever okay to lie to a corrupt person in order to prevent them from committing a grave sin? For context, I have given $2000 AUD to someone who I am 90% sure is a scammer. He poses as someone helping disabled children in Uganda and used the song 'Oceans' on one of his videos with the lyrics 'Spirit lead me' to encourage people to donate. A contact in Uganda has done a thorough research and concluded that he is a scammer. Edit: From a purely human perspective, telling him I will report him unless he repays me the money I sent him (which was a loan) might discourage him from scamming others and using the name of the Holy Spirit in vain as he may have done, as he would not gain as much profit from what is probably his scam venture, but I am uncertain if this is the right approach. To be clear, in reality I will report him regardless. This would just be to encourage him to return the money.