MONTGOMERY, Ala. (AP) — An Alabama man pleaded guilty to detonating an explosive device outside of the state attorney general’s office, federal prosecutors said on Friday.

Kyle Benjamin Douglas Calvert constructed the bomb out of nails, firecrackers and screws, and then set it off outside of Attorney General Steve Marshall’s office in downtown Montgomery in the early morning hours of Saturday, Feb. 24, according to a complaint filed by prosecutors. No people were hurt, and nearby buildings were not damaged.

The bomb was not discovered until Monday, Feb. 26, according to a statement from the Alabama Law Enforcement Agency. Law enforcement arrested Calvert two weeks later.

“Public servants should never be targeted for doing their jobs,” U.S. Attorney General Merrick Garland said. “The Justice Department will not tolerate such conduct, and we will use every resource at our disposal to prevent these attacks and hold perpetrators accountable.”

Calvert, 26, pleaded guilty in federal court to the malicious use of an explosive device. Calvert faces a minimum sentence of five years and a maximum of 20 years in prison with no possibility of parole.

Calvert’s federal defenders declined to comment to an email sent on Friday.

Prosecutors said that Calvert had placed stickers reflecting a wide range of political ideologies around the area, some of which included the phrase, “Support your local antifa.” But the plea deal Calvert signed said that he does not have any “affiliation with antifa,” prosecutors said.

Calvert’s sentencing hearing will be scheduled for the coming months.