The prosecutor previously charged Christopher Wayne Dillingham with possession of a bomb or explosive device with intent to use for an unlawful purpose, which is a felony.
If convicted, the 45-year-old could face up to 20 years in prison. He's also charged with reckless endangerment.
Dillingham appeared in court Monday in Stevenson and was ordered held on $500,000 bail. The new charges will be filed at Dillingham's next court appearance.
In court papers, investigators said Dillingham attached a fireworks bomb to the dog's collar early Sunday and set it off with a blast that alarmed neighbors.
Dillingham said he killed the dog because an ex-girlfriend had "put the devil in it." He also said he was preparing for the rapture.