Agents served search warrants today at two homes IN Pittsburg.
The IRS says dozens of people filed returns using the two addresses, claiming the $7,500 first time home buyers credit.
In each case, the filers claimed no income or interest payments on their returns, raising red flags with the IRS.
"We're getting evidence to put this case together, but this particular scheme involves 44 particular returns claiming that credit, about $323,000 in refunds going out," said Arlette Lee from IRS Criminal Investigations.
No arrests have been made so far.
The IRS investigated a similar scheme in Brentwood and Oakley in March.
The IRS paid out more than $2 million in refunds before catching on and was processing forms worth another $4 million in refunds.