An alleged white supremacist was arrested in Colorado for plotting to blow up one of the state’s oldest synagogues, federal court records released Monday show.

Richard Holzer, 27, was taken into custody Friday after federal authorities supplied him with pipe bombs and dynamite that he planned on detonating at Temple Emanuel, built in the city of Pueblo in 1900, the records allege.

Holzer was charged with the attempted use of explosives and trying to obstruct the free exercise of religious beliefs, according to the documents.

Richard Holzer. El Paso County Sheriff's Office

After his arrest, Holzer confessed to the plot, describing it as his “mountain” while using derogatory terms to describe Jews and Temple Emanuel, the documents say.

Holzer added that he didn’t plan to hurt anyone, though he would have gone through with the attack if someone was inside, according to the documents.

It wasn’t clear if Holzer has a lawyer. Court records didn’t list one.

The records show that undercover federal investigators reached out to Holzer in September after he promoted racially motivated acts of violence on Facebook.

Holzer claimed to have hired a Mexican man to poison the synagogue’s water supply last year, the documents say, and was now preparing for a "racial holy war."

Holzer attributed his belief in the event to Matt Hale, the one-time leader of a group that the Southern Poverty Law Center, which tracks hate groups, described as a white supremacist religious organization.

In 2004, Hale was convicted of soliciting the murder of a Chicago judge and sentenced to 40 years in prison.

In a report last month, the Anti-Defamation League said that anti-Semitic incidents were on track in 2019 to remain “historically high.”

The Jewish civil rights group counted 780 cases of vandalism, arson and the distribution of white supremacist propaganda at Jewish institutions.

The worst year on record since the group began counting such incidents three decades ago was 2017, when it recorded nearly 2,000 acts of anti-Semitism.