PORTLAND, Ore. (AP) — A 19-year-old man admitted he threw a large firework at the federal courthouse in Portland during mass protests last year.

Gabriel Agard-Berryhill pleaded guilty to willfully using an incendiary device in an attempt to damage the courthouse on July 28, 2020, causing more than $1,000 in damage, The Oregonian/OregonLive reported.

Under a plea deal, his lawyer says he’s expected to be sentenced to time served with two years of supervised release for the felony conviction.

Agard-Berryhill appeared before U.S. District Judge Karin J. Immergut.

The firework struck protective wood covering the federal courthouse entrance and set it on fire, federal authorities said.

Agard-Berryhill told federal officers that an unknown man handed him what he thought was a spinner-type firework about the size of a piece of chalk that would rotate with varied colors when lit, according to a federal affidavit.

He said he was going to light it and throw it toward a street, but others said some people had post-traumatic stress from tear gas launched by federal officers and directed him instead to throw it toward the courthouse, according to court records.

Agard-Berryhill said he was shocked to hear the sound that it produced and it scared him, according to an affidavit. He told federal officers he didn’t intend to hurt anyone.