The nationwide probe involves 1,215 criminal defendants in cases that involve more than $2.3 billion in losses.
The Justice Department also has engaged in civil enforcement actions to recover more than $147 million in the operation.
Attorney General Eric Holder said the government will use every law enforcement tool available to prosecute those who prey on vulnerable homeowners.
Hundreds of FBI agents are working on task forces with other law enforcement agencies, FBI Director Robert Mueller said in prepared remarks.
The Justice Department said that the probe, called Operation Stolen Dreams, has resulted in significant criminal cases in Chico, Calif.; Miami; Detroit; Duluth, Minn.; New Jersey, and Atlanta.