Everywhere he goes, retired New York City cop Bruce DeCell carries a forged copy of a Matricula Consular identification card used by millions of illegal Mexican immigrants.
And everywhere he goes -- into airports, train stations, and government office buildings -- it seems the card is accepted without question.
Last week, he used it to breach security at the Department of Homeland Security in Washington, D.C.
"I'd like to just run screaming through places so that people wake up and check it," DeCell told ABC News' Law & Justice Unit.
The card, which DeCell bought from a forger on a street corner in California, lists his address as "123 Fraud Blvd.," on "Staton Island, N.Y." His place of birth is listed as "Tijiuna, B.C."
A homeland security spokesman acknowledged the security breach to ABC News and said an investigation was under way.
In recent years, the Mexican government has issued millions of Matricula Consular cards. The official purpose is to help identify Mexican nationals living or working outside of Mexico. U.S officials say the cards are unreliable forms of identification and prone to fraud and misuse.
DeCell's personal experiment in homeland security began in the fall of 2002. He had lost a son-in-law in the World Trade Center attacks on Sept. 11, 2001, and had become increasingly skeptical about the government's ability to protect its citizens.
Everywhere he looked, he said, he saw "'for show' kind of security.'"
"I'm always thinking about security everywhere I go," he said. "If you thought like I did, the average person would go crazy."
He first used the card in 2002 at the lobby security desk of a public building that houses the offices of the New York State Attorney General. From there, he used the card in airports and train stations around the country, with no questions asked.
"I'm seeing all this 'for show' kind of security, and here's a vulnerability a machine gun can't stop," he said. "This card can get you right into anywhere."
DeCell is a founding member of 9/11 Families for a Secure America, an organization started to promote stronger national security.
He was at the Department of Homeland Security headquarters on June 7 for a scheduled meeting between homeland security officials and his group. He had called ahead and provided the department security with his name, address, and date of birth.
"I have used this card probably 18 to 20 times," he said. "The hardest anybody has ever looked at it was at homeland security."
DeCell said the guard looked at the card for what seemed like three minutes or four minutes.
"The thing is, she studied it for a while and I thought for sure I would be captured," he said. "It's just common sense. … And my birthday was not even the same."
Eventually, DeCell said, "Then she just wrote the information down on a pad and let me through."
DeCell believes more emphasis must be placed on training security guards and paying them better.
"They must be telling [the guards] to hurry up, keep things moving," he said. "It's a boring job. They are like potted plants. I bet if they promised the guards a bonus -- $1,000 -- I bet they'd catch every one of those fake IDs. Right now, it's just a formality."
Department of Homeland Security spokesman Jarrod Agen told ABC News that the Matricula Consular cards were not valid forms of identification for entry to the department's headquarters.
"We are taking the necessary actions to make sure there's not another occurrence of this type," he said.
Agen said that with prearranged meetings like the one DeCell's group had scheduled, that visitors were requested to call ahead with their name, date of birth, and Social Security number, which were then "vetted" by the government.
When the visitors arrived, Agen said, homeland security officers "checked their photos and the name against the information they had at the visitors center."
"We verified that he was with the group we were expecting and that he was the person we were expecting," Agen said.
DeCell and the other members of his group were then sent through metal detectors, Agen said.
Agen could not say whether the security guard who had accepted DeCell's forged Mexican ID card had been reprimanded or suspended. "I do not have details on that," he told ABC News.
DeCell said he didn't regret taking advantage of his invitation to meet with homeland security officials.
"Living in a democracy is not a spectator sport," DeCell said. "People have to devote their time and energy, and contact their local officials if they're not doing what they need to be doing for our country. That's the only opportunity we have."