Sales Involving Assignment Contracts Between Owner and Wholesaler/Investor

[Jon B.]

I am a buyer and am not familiar with assignment contracts. I have come across multiple properties - typically houses that require rehab - where the seller is not the owner of the property but what I believe to be a wholesaler or investor who has been assigned the rights of the property to sell to an end buyer (me) for a (substantial) fee. Often, the seller in the sales contract is not the owner but the wholesaler/investor. The owner actually largely remains anonymous and I only deal with the wholesaler/investor. Are there any considerations I should be aware of and account for when under contract with a property owner who has an assignment contract with a wholesaler/investor? What kind of due diligence should I be doing to protect myself?