12-15% Cash-on-Cash return- too good to be true?

[Yonah Weiss]

I know a successful HML based in NJ lending mostly in Tri-state area, on creative loans that most lenders turn down. He runs a conventional fund, that lends HM on standard deals, but bunch of deals fall through the cracks, that the fund cannot do for one reason or another. So he has been funding them with private investors, and offered me to join in. There is moderate risk involved, which is why he can charge a higher rate for these deals

He is offering very attractive returns for investors, but it seems too good to be true. 12-15% (annually, usually with monthly payments) returns to investors.

Does anyone have experience with this type of investing?