The man authorities say left an explosive device at Asheville Regional Airport on Friday morning that contained ammonium nitrate and fuel oil said he was preparing to "fight a war on U.S. soil," according to a criminal complaint filed in federal court.

The suspect, Michael Christopher Estes, had his first appearance in federal court Tuesday morning. He is charged with attempted malicious use of explosive materials and unlawful possession of explosive materials in an airport.

He waived his right to a preliminary hearing, answering several of the judges questions with a polite, "Yes, sir." Near the end of the proceeding, Estes, bald and wearing a brown prison jumpsuit, smiled and shook the hand of his attorney, Fredilyn Sison, an assistant federal public defender.

The federal judge found that Estes is indigent and assigned him an attorney for upcoming proceedings. Sison said that would likely be her.

The criminal complaint, filed by FBI agent James A. Anderson and read in court, states that airport police officers found "what appeared to be an improvised explosive device" early Friday morning outside the airport terminal.

After being taken into custody at the Asheville Police Department, Estes waived his rights and agreed to answer questions, the complaint states. Estes "admitted that he placed the explosive device at the Asheville Airport," the complaint states. "He also explained that he bought the precursor materials at Walmart and Lowe's" in Arden.

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"Estes claimed that he was getting ready to 'fight a war on U.S. soil,' but also claimed that he did not actually set the alarm clock," the complaint states.

The complaint also states that, "Estes described how he created the device using ammonium nitrate and the Sterno as a fuel source and then rigged the alarm clock to strike the matches and cause the flame necessary to trigger the device. Estes admitted to putting the nails in the device as well."

On Friday, a TSA officer tested the substance in the device and it was positive for ammonium nitrate, a "widely used and regulated bulk industrial explosive," the complaint states. A bomb dog approached the device and "signaled," indicating "the presence of an explosive material.

"The device at the airport consisted of a Mason type jar with a lid that was locked down by an incorporated locking device," the complaint states. "There were prills -- pellets or solid globules of a substance formed by the congealing of a liquid during processing -- inside the jar and two plastic cups containing an unknown liquid substance, believed to be the fuel source," the complaint states. "There were pieces of cold compress packs inside the jar."

Once ammonium nitrate forms into prills, it can absorb the fuel oil needed for an explosion, the complaint states.

"The jar was filled with steel wool that was then wrapped around nails and one shotgun cartridge," the complaint states, noting that it was a 410 gauge. "There was an alarm clock taped to the outside of the jar. There was then a grouping of matches taped to the striker arm positioned between the bells, and the bells were removed."

The clock was set to go off at 6:00.

Video footage from the airport showed an individual walking onto airport grounds at 12:39 a.m. on Oct. 6. He was wearing black clothing and a black cap and carrying a bag.

"Based on a review of the video, the individual walked near the entrance to the terminal, went out of sight momentarily, and was then seen departing the area without the bag," the complaint states.

An airport maintenance worker said a man had come out of a wooded area across the street and to the east of the airport. Investigators found a bag in the woods with Gorilla Tape, consistent with the tape used in the device, as well as Sterno Firestar Gel, believed to be the likely fuel source for the explosive device, the complaint states.

There was also a bag containing shotgun shells.

Investigators went to the Walmart store on Airport Road, where they learned a person had bought Gorilla tape, Sterno Firestarter Gel, a glass Mason type jar, matches, cold compress packs, and an alarm clock on Oct. 3. At the Lowe's store off Airport Road, investigators learned a person had bought Kobalt gloves that were "very similar to those observed in the tool bag found in the wooded area."

The backpack bag found in the woods apparently had been bought at REI in Biltmore Park, and the buyer used a membership number assigned to Michael C. Estes. Estes admitted that the bought the backpack at REI, the complaint states.

Officers arrested Estes, 46, on Airport Road on Saturday, after several people reported seeing him nearby. His last known address was in Asheville.

No one was injured in the Friday incident. The airport's Terminal Drive and part of a terminal were closed for about two hours.

In the complaint, investigators noted that the type of device found at the airport, called "AN/FO" explosives, has been used "in a number of terrorist-related incidents around the world in the past.

"When AN/FO comes into contact with a flame or other ignition source it explodes violently," the complaint states. "Shrapnel or nails or ball bearings are often items added to the device so as to increase the devastation inflicted by the explosion."

Estes told investigators he "staged" in the woods near the airport a couple of days before placing the device at the airport.