Reports of mortgage fraud, which have been increasing since the housing boom, rose to their highest level on record in 2010, Treasury Department figures showed.

The Financial Crimes Enforcement Network, a Treasury agency, reported 70,472 "suspicious activity reports" related to suspected mortgage fraud, up from 67,507 in 2009, or a 5% increase. That's the highest number recorded by the government since tracking began in 1996.

At...