Christopher Dillingham, a Washington state fireworks seller, pleaded not guilty Thursday to blowing up his dog with explosives.

Dillingham, 45, of Stevenson, Wash., allegedly blew up his 3-year-old Labrador retriever – a gift from his ex-girlfriend – because he believed it was possessed by the devil, authorities told the Associated Press earlier this month.

Dillingham pleaded not guilty Thursday in a Skamania County courtroom Thursday to charges of possession of a bomb or explosive device with intent to use for an unlawful purpose, animal cruelty, a fireworks violation, and reckless endangerment, prosecutors told CNN. He faces up to 20 years in prison if convicted of the most serious charge.

The animal cruelty charges were filed after the other offenses because investigators initially said that the 3-year-old dog didn’t suffer during the incident.

Dillingham, who owns a fireworks business, allegedly told authorities he was preparing for “the rapture” when he strapped explosives to the dog’s collar. Authorities said the dog died instantly, according to the AP.

Neighbors called the Skamania County Sheriff’s Department about loud explosions coming from Dillingham’s home around 3:45 a.m. Aug. 6. Deputies discovered the dead dog’s remains on Dillingham’s property.

Dillingham reportedly told authorities he was preparing for the end of the world, which he believed was imminent due to a nuclear attack. He also allegedly told sheriff’s deputies that his ex-girlfriend gave him the dog and that she “put the devil in it.”

When Dillingham allegedly strapped explosives to the dog, he distracted the lab with treats so it wouldn’t try to knock them off its collar. He allegedly told police he made the explosives from black powder derived from fireworks.

Dillingham remains in the Skamania County Jail, where he has been holed up since Aug. 4. He was unable to come up with the $500,000 bond set by a judge.