A man who planted a Mason jar filled with explosive chemicals and nails at a western North Carolina airport last week vowed to “fight a war on U.S. soil,” according to court documents released Tuesday. The criminal complaint accuses Michael Christopher Estes of attempted malicious use of explosive materials and unlawful possession of explosives at an airport.

According to CBS News, the complaint, which was written by an FBI agent, said investigators found the improvised explosive device Friday morning at the Asheville airport near a terminal entrance. Asheville police bomb technicians then rendered it safe.

Person of interest identified & detained. Federal investigation ongoing. https://t.co/K7QjOrbH0G

— FBI Charlotte (@FBICharlotte) October 7, 2017

Court documents say that the authorities found the improvised explosive device around 7 a.m. Friday at Asheville Regional Airport. The IED contained ammonium nitrate and Sterno fuel, along with steel wool that was then wrapped around nails and a .410 gauge Winchester shotgun cartridge. An alarm clock was taped to the outside of the jar with and matches were attached to the arm that strikes the bells of the alarm clock. The alarm had been set for Friday at 6, according to the complaint.

Surveillance video showed Estes dressed in black pants, a jacket, and black hat approaching the terminal entrance shortly after 12:30 a.m. Friday and appearing to leave behind a bag, the FBI agent wrote. In nearby woods, investigators later found a backpack and a toolkit containing similar items to what was used in the explosive device: tape, Sterno fuel, and more shotgun shells. Investigators determined such items had been purchased at nearby stores earlier in the week, providing more surveillance video.

Estes was arrested Saturday, and the complaint says he admitted to leaving the explosive device at the airport. The complaint also states that Estes “claimed he was getting ready to ‘fight a war on U.S. soil,’” but didn’t elaborate on this alleged motive. He was being held at the Buncombe County jail without bond after a brief court hearing Tuesday. Jail records list him as a 46-year-old Native American.

The complaint said Estes waived his Miranda rights, answering questions and admitting to the building and planting of the device. “Estes described how he created the device … and then rigged the alarm clock to strike the matches and cause the flame necessary to trigger the device,” the complaint states. “More specifically, the alarm clock would go off, the matches would strike, the Sterno would heat up, and then the Ammonium Nitrate would explode.”

Estes claims he never actually set the device to go off, but the criminal complaint alleges that he had.