How does mortgage fraud affects the subprime mortgage crisis?

In the actual Subprime mortgage crisis in the US huge amounts of mortgage frauds were discovered. What’s the part that these frauds played in the actual mortgage crisis ? Thanks.

Related posts:

1. What Is A Subprime Mortgage?
2. Unaffordable Mortgage Rates Are not Sole Cause for Foreclosure Crisis
3. Obama To Tackle Mortgage Crisis This Week
4. What Is A Subprime Home Loan?
5. The Mortgage Crisis and Who Is To Blame