The FBI says it has arrested a white supremacist who was planning an attack on a Colorado synagogue, describing the plan as “domestic terrorism”.

Richard Holzer, 27, of Pueblo, Colorado, is accused of plotting to attack the city’s Temple Emanuel synagogue. His co-conspirators included two undercover (UC) FBI agents.

Holzer allegedly expressed a desire to “get that place off the map”, and was not concerned if anyone would be hurt in the attack because they “would be Jews”.

He allegedly said that the bombing would be “a move for our race”.

Holzer was arrested on 1 November in Pueblo, after he had gone to a motel with two undercover agents to pick up explosives.

Holzer allegedly described the pipe bombs and sticks of dynamite proffered by the agents – actually dummies manufactured by the FBI at Quantico – as “absolutely gorgeous” and said they should go ahead with the attack overnight to avoid police. Earlier in the evening, he had displayed a Nazi armband and produced a copy of Adolf Hitler’s book Mein Kampf, a mask, and a knife from a backpack, according to authorities.

In a press conference Monday afternoon, Dean Phillips, the special agent in charge of the FBI in Colorado, said that the agency had started investigating Holzer after receiving a tip in September about his social media behavior. Then followed more than a month in which FBI agents posing as fellow white supremacists led Holzer to reveal the extent of his violent beliefs and fantasies.

Holzer made contact on Facebook with an FBI Online Covert Employee (OCE) who was posing as a female supporter of white supremacy in late September. He allegedly sent pictures of himself adorned with white supremacist symbols, a video of him wielding a machete, photos of him apparently urinating on a Jewish center, and another video of him wielding a knife, saying “fuck antifa”.

He repeatedly expressed beliefs indicating virulent antisemitism and a deep inculcation in the beliefs of the white supremacist movement, according to the court documents. He allegedly told the undercover agent was preparing for “racial holy war”.

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He also claimed to have paid a “Mexican cook” $70 to “hex and poison a local synagogue” and said the the cook had put arsenic in the synagogue’s water pipes, the court documents said.

The agent offered to introduce Holzer to “friends” visiting Colorado, who were in reality undercover agents. Online, he explained to one of them a plan to once again poison the synagogue.

On 17 October, undercover agents arranged a restaurant meeting with Holzer and his friend “Skeeter”. Holzer allegedly arrived with white supremacist paraphernalia as gifts, reiterated his belief in a holy war, and said he had paid a “witch doctor” to curse the synagogue.

He then canvassed the possibility of attacking the building with Molotov cocktails, in order to “vandalize the place beyond repair” and to do something that “tells them they are not welcome in this town”, according to investigators. The exchange was peppered the exchange with antisemitic slurs, according to the documents. Holzer, Skeeter and the undercover agents then cased the synagogue.

In subsequent online conversations, Holzer allegedly solicited the supply of more powerful explosives from the agents. He met with one of them on 31 October and made a plan to meet at the motel the following night in order to carry out the plot, which would involve bombing the synagogue in the early hours of Saturday 2 November.

When he showed up at the planned meeting, Holzer was arrested. In interrogation, according to the affidavit, he admitted to the plot, calling the plan “my mountain”, and described Jews and the synagogue as a “cancer”.

In a press conference on Monday, the Colorado US attorney, Jason Dunn, said Holzer had been charged with obstructing persons in the enjoyment of their free exercise of religious beliefs, through force and the attempted use of explosives and fire, which carries a possible penalty of 20 years in prison.

Holzer remains in federal custody. His next hearing will take place on 7 November.