If true fill out scam report here with all details: https://bitcointalksearch.org/topic/scam-report-format-use-it-to-make-scam-reports-properly-260073 and he will be tagged by others.
Also IF TRUE you should go into his trust page here https://bitcointalk.org/index.php?action=trust;u=2683898 and send him negative feedback and in same place (after you do scam report) set a type 3 flag here https://bitcointalk.org/index.php?action=trust;addflag=2683898 using the scam report thread on him as a reference which will put a large banner over his posts that he is a scammer once "supported" by a couple others. Of course he will just come back as another scammer but at least if true this one will be gone for a few minutes.