A federal grand jury in Denver has indicted Richard Holzer on charges stemming from an alleged attempt to blow up a synagogue in Pueblo, Colorado, earlier this month .

The 27-year-old Pueblo resident faces two new charges attempted arson and using fire or an explosive device to commit a felony offense in addition to the original charge of attempting to obstruct religious exercise by force and use of explosives and fire.

FBI agents arrested Holzer on Nov. 1 after he allegedly told covert officers he planned to attack Temple Emanuel. According to authorities, he also said he had paid someone $70 to poison the synagogue by putting arsenic in the buildings water pipes on Oct. 31 last year.

Authorities say Holzer accepted dummy explosives from the undercover agents, including inert pipe bombs and dynamite, for a planned attack early the morning of Nov. 2.

According to an FBI complaint, Holzer claimed to have been a member of the Ku Klux Klan who later identified as a skinhead. He managed several Facebook accounts that he used to promote white supremacist ideology and racist acts of violence.

Holzer is in federal custody and is scheduled to be arraigned on Monday. He faces a maximum 50-year prison sentence if convicted on all counts.