SAN DIEGO -- Kurt Erlandson spotted it right away.

"So they charge you; plus they charge you for a late fee. I knew it was bogus," said Erlandson.

Erlandson is referring to an official-looking letter that arrived in the mail. It informs people that their property values have dropped and there is a need to reassess in order to lower the tax bill -- all for a fee.

"I was concerned; say mad, that people were doing this. I know probably the elderly would get hit hardest," said Erlandson.

He has reason for that concern because he said, "It says you're required to do this, and there is no requirement."

Erlandson is right; homeowners do not have to pay anything to reassess their property value.

San Diego County assessor Gregory J. Smith said, "They can do it themselves through our office, the clerk's office, at no cost to themselves."

Smith said companies have the right to offer the service as long as they don't misrepresent themselves as a governmental agency.

"What bothers me is there are a lot of firms out there that are pushing the envelope," said Smith.

One envelope looked so real that the post office was fooled when they had to return to sender.

"The post office returned it and they didn't return it to this company. They returned it to us. So they themselves, the post office, got confused," said Smith.

Officials said when the words "property tax reassessment requires you to respond to this notice" appear, don't be concerned. Homeowners do not have to pay them.

The district attorney is investigating a few companies for alleged fraud violations.

Homeowners who have received these types of letters are being asked to send them to the district attorney's office.

The district attorney's office can be contacted at 619-531-4070.