The number of mortgage-fraud cases the FBI is investigating is on the rise as scammers prey on unsuspecting homeowners behind on their mortgage payments and nearing foreclosure.

"Considering that there could be more than 3 million foreclosures starts in 2009, it is safe to assume that frauds and scams will affect a large number of American homeowners," said Travis Hamel Olsen, president of the National Short Sale Center, in a news release this week. The firm facilitates short sales on behalf of homeowners and real estate agents.

"Unscrupulous companies use myriad ways to take advantage of unsuspecting homeowners," he said. Scammers can get away with thousands of dollars from homeowners in distress, the release said.

The FBI is currently investigating more than 2,100 mortgage fraud cases, according to a podcast on the FBI Web site. Listen to the FBI podcast about mortgage fraud cases.

In 2008, the FBI was working on more than 1,600 pending mortgage fraud cases; in 2007, there were more than 1,200, according to figures cited during the podcast. Back in 2003, the FBI was working on more than 400 pending cases.

To protect against becoming a victim of mortgage fraud, get referrals from friends and relatives when selecting a real estate professional to work with, said Brian Weber, a special agent and member of the FBI's Mortgage Fraud Team.

"We also notify people to be extremely wary of strangers or unsolicited offers for help; people who come to you to offer you assistance. We also ask people to know and understand the terms of the mortgage and the documents they sign," he said.

Read more real estate news in this week's pages, including the latest foreclosure numbers and why mortgage rates have been going up. Plus, read a Realty Q&A about how first-time home buyers can use the federal tax credit at closing.

If you're in danger of losing your home to foreclosure, don't fall for deceptive offers, whether they come in the form of a phone call, a letter, an advertisement or an email. "Usually if the deal seems too good to be true," Olsen said, "then it probably is."

-- Amy Hoak , Real Estate writer