It's called "mortgage fraud".

Based on the circumstances you may be able to charge them with fraud or criminal charges depending on what information was on their application.  

Otherwise you risk the new conventional lender believing you've committed fraud, and the new FHA lender for the multi-family questioning why you've just refinanced into a conventional loan as primary, and now you're trying to purchase a multi as primary as well.

@Peter Sik your PM is probably using a property management software program to process this echeck. echeck's are essentially identical to ACH payments and are super secure.

No, it's called mortgage fraud.

My neighbor has an Identical duplex and is currently in the process of evicting everyone from the house due to drug issues (he doesn't live there he uses it solely as an investment property).

I read about mortgage fraud and penalties and it stresses me out even more.

Locking up property, and then walking if not able to assign, and no intention to purchase is FRAUD BY INDUCEMENT.

Very unless you qualify due to an unforeseen circumstance change like a job transfer otherwise if you sign papers saying you'll live there for a year, you better honor it or risk mortgage fraud. 

Tax fraud is no joke.