There are many Web sites on the Internet that tell people how to report illegal immigrants. Most groups sponsoring those sites direct concerned residents to a government-sponsored, free tip line.

But one business gaining notoriety goes a step further and offers to act, for a fee, as the middleman between citizens and federal authorities.

The Web-based service charges customers $10 to file reports with federal agencies about suspected illegal immigrants.

Immigrant-rights groups say they are concerned about the business because they believe it could stir anger aimed at illegal immigrants.

Dave Caulkett, a Florida man, founded the private, for-profit Web site, called ReportIllegals.com. It aims, he said, to facilitate reporting illegal immigrants and business owners who hire them to federal authorities, including the FBI and Department of Homeland Security.

Federal authorities said they are discouraging people from using the site, pointing out that immigration agencies have their own free tip line to report immigration crimes.

Other anti-illegal-immigrant groups that offer information on how to report illegal immigrants on their Web sites include Voice of Citizens Together, American Border Patrol and Stop the Invasion.

Caulkett's site has been around for about a year, but recently the service has received national and international media attention, causing business to skyrocket, Caulkett said in a phone recent interview with the North County Times.

Caulkett wouldn't say how many hits his site had received, but did say his business tripled after a story about the Web site ran in the Orange County Register.

"It's not a lucrative business, but it's getting to be," he said.

The service has some immigrant advocates worried that the site may foster hatred against illegal immigrants and may exploit people's anger at immigrants for profit.

"It's easier to stir public anger with fear and loathing of immigrants than it is to understand the very important, positive role that immigrants play in this country," said Rick Swartz, an immigration attorney and founder of the National Immigration Forum, a immigrant-rights advocacy group.

Swartz said he is concerned that the Web site could be misused to report legal immigrants and that it raises legal questions, such as possible slander. But he added that he was not familiar enough with the service the Web site provides to form a legal opinion.

Officials with the U.S. Immigration and Customs Enforcement, an investigative arm of the former Immigration and Naturalization Service, said the site is not government-sponsored and that the federal agency has its own toll-free service where people can report illegal immigrants.

"We highly recommend that the public use our toll-free tip line, and individuals can be assured confidentiality and that we respond to all leads," said Lauren Mack, a spokeswoman for Immigration and Customs Enforcement in San Diego.

Mack said that all leads, including those the agency receives from Caulkett, are thoroughly investigated by immigration officials paying close attention to false accusations. Mack said she didn't know how many cases the federal agency has received from ReportIllegals.com.

Caulkett said the government's tip line often frustrates people because they are often put on hold. He also complained that, in his view, people find it difficult to keep straight the various phone numbers needed to report crimes to different agencies.

"People have a hard time finding the number or the number is busy," Caulkett said. "In some areas, (federal offices) don't even accept reports except in writing."

Caulkett, of Pompano Beach, Fla., lost his job in information technology a year ago and decided to merge his work as an anti-illegal immigration advocate with his work in computers, he said. He had been running another Web site that targeted illegal immigration before he got the idea for ReportIllegals.com.

The Web site offers "a simple, fast and anonymous way to report illegal immigrants and their employers," Caulkett said. But he can't guarantee that complaints will be quickly acted upon, he said.

To file a complaint, customers are asked to fill out as much information about the suspected illegal immigrants and their employers as they have, such as name, address, nationality, age, gender, and recognizable marks, such as tattoos.

The $10 fee can be paid by check or credit card.

Depending on the information, Caulkett said, he files complaints with the Department of Homeland Security, Social Security Administration, Internal Revenue Service or FBI.

"I've been surprised by the level of detailed information that people provide," Caulkett said. "It's clear that the people who report know these individuals."

Caulkett rejected the accusation that his Web site fosters hatred or racism.

"The fact is that a good portion of our clients are Hispanics," he said. "I firmly believe that legal Hispanics are not (illegal immigrant) advocates."

He added: "I try to at least equally focus on the employer. I know that I'm pushing the envelope, but I reject any notion that race has anything to do with it."

The U.S. Immigration and Customs Enforcement's free tip line is (866) 347-2423.

Contact staff writer Edward Sifuentes at (760) 740-5426 or esifuentes@nctimes.com.