FBI questions Home Depots about bomb-making materials

DENVER - 9Wants to Know has learned that FBI agents have been going to Home Depots across the Denver area to look through receipts for purchases of large quantities of chemicals that can be used to make explosives.

Sources say the agents had credit card numbers and were looking for two or three individuals who purchased muriatic acid and another strong chemical used to clean concrete. The agents also asked if the stores would be able to provide them video of specific dates and times that purchases were made.

The FBI will not say if the search is part of the ongoing terror probe involving Najibullah Zazi of Arapahoe County. Agents raided his home and one of his relative's homes on Wednesday. Agents also raided his friends' houses in New York City on Monday.

They searched Zazi's rental car and found instructions about how to make bombs.

Muriatic acid is hydrochloric acid that is legitimately used for masonry work, cleaning concrete and oil spills. Chemists say it can be easily converted into an explosive device.

"You can mix it with hydrogen peroxide and acetone to make TAPT (triacetone triperoxide). Its crystals are more explosive than TNT," chemist Lynn Reimer said who owns a meth-lab clean-up company called ACT On Drugs, Inc. "The crystals are shock-sensitive that go off when they dry."

Reimer says that kind of chemical explosive was used by Richard Reid, the so-called shoe-bomber, who tried to light the fuse on the explosives in his shoes on a flight from Paris to Miami in December 2001.

Terrorists also used chemicals in homemade devices in the London Subway bombings in July 2005 which killed 56 people. Muriatic acid was also used by suspected terrorists in their plans to blow up airplanes from the United Kingdom to the United States in 2006.

Colorado's State Chemist says that the commercial industrial chemical can easily be converted in a bomb within a day if someone knows what they are doing. Even then, State Chemist Ken Niswonger says it's extremely dangerous.

"The manipulations are hazardous because we're talking about commercial chemicals being used for a purpose in which they were not designed. There's a lot of risk in it," Niswonger said.

Monday, FBI agents issued a warning to law enforcement in Colorado and across the country to be on the lookout for any materials that could be used to make homemade hydrogen peroxide-based explosives, according to the Associated Press. Officials were also told to watch out for people with burn marks on their hands, faces and arms.

Zazi has not been arrested and maintains his innocence that he is not a terrorist and has no connections to al Qaeda.

Home Depot declined to comment for this story.

If you have any story tips, please e-mail 9Wants to Know Investigator Deborah Sherman at Deborah.Sherman@9NEWS.com.