At least one person is being held in California, accused of stealing hundreds of pounds of the explosive, ammonium nitrate. It is a case similar to one here in Colorado Springs. But, San Diego officials say they don't believe the two cases are related.

Nearly two weeks ago, about 450 pounds of amonium nitrate was stolen from Castle Concrete here in the Springs. That was just days before 700 pounds of the explosive went missing from a construction company in San Diego.

The man in police custody in California is being held on unrelated charges, but officials say they believe he might have been involved.

Agents at the Bureau of Alcohol, Tobacco and Firearms say they're running out of viable leads in the case here in Colorado. They're hoping someone knows something and comes forward and they're asking people to keep an eye out for the 50 pound bags of amonium nitrate.

Experts say amonium nitrate has a distinct smell, very much like diesel oil. It looks like "dipping dots" ice cream, with a pinkish tint.

ATF agents are asking anyone with information that may lead to the missing explosives to contact Crime Stoppers anonymously. In Colorado Springs the number is 634-STOP, in Pueblo, the number is 542-STOP. You could earn a cash reward if your tip leads to an arrest.