The CARES Act created the Office of the Special Inspector General for Pandemic Recovery. Its purpose is to investigate fraud allegations. And the Department of Justice (DOJ) will prosecute any charges.

What is PPP loan fraud? (CARES Act Fraud?)
PPP loan fraud occurs when people intentionally obtain – or attempt to obtain – funds through the CARES Act that they are not entitled to. Five examples of PPP loan fraud include:

Falsely claiming the company has fewer than 500 employees to qualify for the loan.
Falsely claiming the coronavirus crisis hurt business to qualify for the loan.
Inflating average monthly payroll costs to get more loan money. (Note that payroll costs cap at $100,000 per employee.)
Falsely claiming all the loan money is going towards qualified expenses (payroll, rent, mortgage, utilities) in order to get the loan forgiven.
Not disclosing if employees leave (thereby reducing payroll expenses) in order to get more of the loan forgiven.