According to the unsealed indictment, Ian Benjamin Rogers, 45, of Napa and Jarrod Copeland, 37, of Vallejo started plotting to attack Democratic targets after the 2020 presidential election and also tried to get support from an anti-government group to further the cause.
The Justice Department did not identify which group the two men allegedly reached out to for support.
In numerous messages they exchanged, the two discussed blowing up buildings, the Justice Department said.
In one exchange in January 2021, for instance, Rogers told Copeland: "I want to blow up a democrat building bad."
"I agree," Copeland responded. "Plan attack."
Federal law enforcement agents executed a search warrant on Jan. 15 at Rogers' home and seized a stockpile of weapons including 45 to 50 firearms, thousands of rounds of ammunition and five pipe bombs.
Prosecutors say that Copeland tried to destroy evidence during the investigation and communicated with the leader of a militia group who told him to switch communication platforms and delete the evidence.
Rogers was arrested on the day the search warrant was executed and remains in the custody of the state. Copeland was arrested on Thursday and will appear for a detention hearing on July 20, the Justice Department said.