NEW YORK The letter may look like a government form. The logo may seem official. The Web site address may sound like an agency that can help. But there's a good chance it may all be a scam.

The mortgage foreclosure crisis has sparked a cottage industry of “foreclosure rescue” companies. But advocates and government officials warn that a significant number are little more than fraudulent operations designed to separate distressed homeowners from their money, and sometimes their houses as well.

“They prey upon the financially unsophisticated,” said Gail Cunningham of the National Foundation for Credit Counseling. “Anyone can easily fall victim to such scams. When you're hurting, we may all become financially unsophisticated.”

Many of these companies have popped up as the mortgage meltdown accelerated, said Gary Almond of the Better Business Bureau in Los Angeles, one of the areas hardest hit by the housing crisis.

Because of the role the mortgage industry plays in the nation's economy and the types of crimes mortgage fraud represents, these firms have even drawn scrutiny from the FBI. The feds have nearly 2,350 mortgage fraud cases, up almost 400 percent from five years ago.

“With people losing homes, you're at your most vulnerable,” said Roscoe Howard, a Treasury Department spokesman. “It's a lot like being a poor swimmer and being thrown into a lake, you're going to reach for whatever you can.”

Even for wary consumers, it may be hard to tell if the line being thrown by a company will sink you.

Nonprofit agencies working with government programs to help homeowners in danger of foreclosure don't charge for the services they offer, and some states prohibit lenders from charging fees in advance of providing services.

Homeowners can call the federal government's Hope Now program at 888-995-HOPE, or visit http://hope now.com to find legitimate assistance. Details about government programs and counseling referrals are also available at http://www.makinghomeaffordable.gov.

Last month, the FTC sued five companies as part of a crackdown on mortgage modification and foreclosure rescue scams, the latest in a series of lawsuits aimed at such swindlers.

The FTC said these companies tout so-called guarantees and high success rates to mislead consumers about their services; charge upfront fees that legitimate nonprofit organizations do not charge; and use copycat names or look-alike Web sites to appear to be a nonprofit or government entity. The agency also sent warning letters to 71 other firms “that are marketing potentially deceptive mortgage modification and foreclosure assistance programs.” The FTC would not identify those companies.

Some would no doubt be familiar to Dan Crevina, director of operations and marketing at the BBB of New Jersey. He's dealt with at least a dozen companies that stopped answering BBB inquiries, and he now simply refers new complaints about them to enforcement agencies.

“There are certain names that I hear and I know automatically how we're going to end up handling it,” he said. “And the list is growing.”