DENVER -- A 64-year-old man was arrested Saturday in connection with a homemade explosive left outside a police station in Nederland, the FBI said Monday.
David Michael Ansberry was taken into custody as he got off an airplane at Chicago's Midway International Airport.
U.S. attorney spokesman Jeff Dorschner said Ansberry has been charged with attempted destruction of a building or property by means of fire or explosive. He could get up to 20 years in federal prison if convicted.
On Tuesday morning, a Nederland police officer found a backpack outside the station and brought it inside, assuming it had been lost or abandoned.
An inspection of the bag revealed an explosive device and the shopping center at 20 Lakeview Drive was evacuated.
The device was determined to be a "legitimate explosive device" that was armed but failed to go off. The bomb squad detonated it early Wednesday morning.
RELATED: Criminal complaint and affidavit
The arrest affidavit said a cellphone was used as a detonator for the device, and investigators found that another cell phone number "had dialed
the detonator multiple times in an attempt to engage the bomb."
Investigators quickly and methodically were able to find out where the two cellphones were purchased based on the phone numbers assigned to them. They obtained a description of a person who purchased them.
"Upon learning of the description, the chief of police ... remarked that he saw an individual matching that description during evacuations from the Boulder Creek Lodge, a motel across the street from the PD, on the morning that the bomb was discovered," the affidavit said.
The motel was able to confirm it had a guest that matched the description and it provided Ansberry's senior citizen identification card. He is from San Rafael, Calif.
Ansberry is listed as 3-foot-6 and weighing 100 pounds, according to the affidavit.