A man accused of throwing Molotov cocktails into a Colorado group that had gathered to bring attention to Israeli hostages in Gaza planned the attack for more than a year and specifically targeted what he described as a “Zionist group,” authorities said in court papers unsealed Monday charging him with a federal hate crime.

Witnesses in Boulder said the suspect, Mohammed Sabry Soliman, 45, yelled “Free Palestine” and used a makeshift flamethrower and incendiary devices. Eight people were injured in the attack, some with burns, as a group was concluding their weekly demonstration.

An FBI affidavit says Soliman confessed to the attack after being taken into custody Sunday and told the police he would do it again.