In 2013 "American Idol" featured a contestant with a sympathetic story.

"We were on a mission in Ramadi, Iraq, and we came across an IED, and the IED exploded," Matt Farmer said on "American Idol." Farmer served in Iraq, but was never injured in battle and later admitted "it was all lies" in a letter to the website, Guardian of Valor.

"When we outed the guy from 'American Idol', that pretty much started this whole thing," Guardian of Valor founder Anthony Anderson said.

Anderson may be the country's most prominent "stolen valor" detective. "Stolen valor" is a term applied to those who falsely claim military service, either to gain recognition or, in some cases, money. It's offensive for many Americans to think of, but it's real, and because the government often doesn't have the resources or time to investigate, private citizens pick up the slack, reports CBS News correspondent Jeff Glor.

From his South Carolina basement, Anderson works day and night separating military fact from fiction.

"We've had family members turn their own family members in. It's crazy sometimes. I've had sons turn their dads in. I've had dads turn their sons in. It's wild," Anderson said.

The website features a "Hall of Shame" and links to video confrontations.

One video shows a man claiming to be an Army ranger being challenged while shopping. It has been viewed nearly six million times on YouTube.

"Do you get mad at these people? Do you feel sorry for them?" Glor asked.

"Originally in the beginning, I did. I felt angry and I felt sorry for some of them, but now it's just, I really don't feel anything. I just know that I'm protecting what our brothers and sisters have earned overseas," Anderson said.

False claims of battlefield glory have been made as long as there's been war, but confrontations now can easily escalate in intensity.

"Some of it can come off as the work of vigilantes. It can even get dangerous if somebody's falsely accused," Glor pointed out.

"And we have never falsely accused anyone," Anderson said.

"You don't consider yourself a vigilante?" Glor asked.

"Not at all. No. We don't go chasing these people. We give them all a chance to explain themselves," Anderson said.

Joe Plenzler represents the 2.2 million veterans of the American Legion and sees Anderson's work as a service to the men and women who fought honorably.

"Honor is a very important concept to us. So we don't really look kindly on those who lie, cheat, steal," Plenzler said.

Anderson, who served more than 13 years in the Army, including a tour in Afghanistan, funds the site through donations. He can spend years on an investigation and says he won't expose someone unless he's 100 percent.

"I've got six or seven guys that are constantly working these emails," Anderson said.

"People never learn?" Glor asked.

"They never learn," Anderson said.

"The attraction of that glory is..." Glor said.

"It's just too great for some people. They would rather impersonate instead of actually go raise their hand and serve their country," Anderson said.

One of the issues is the services often don't talk to each other, so it can be very challenging to figure out whether someone did what they said. There is also no comprehensive list of medals awarded by the military. Anderson believes that should change.

