A California man arrested after several police officers were injured in an explosion at a July march reportedly told authorities he gave the incendiary device to a teen and told him to throw it.

Giovanni Gaines, 23, was arrested last week for his alleged involvement in the blast, which injured 10 Oakland police officers during a July 23 march honoring Nia Wilson, Lt. James Beere said Thursday, according to the SF Gate. Wilson had been fatally stabbed at a BART station a day earlier in what initially appeared to be a racially motivated attack, though, it later emerged the suspect had mental health issues.

Police moved in to break up the rally after a group of marchers attacked a man they allegedly thought was a white nationalist, Beere said. As officers tried to de-escalate the situation, an IED suddenly flew their way. The resulting explosion injured 10 officers, including Beere, according to the SF Gate.

Police arrested a 13-year-old boy in connection with the explosion, and he reportedly confessed to tossing the device, which was described as an altered M-1000 firecracker. The teen said, however, he was given the device by an adult who instructed him to “throw it.” Beere said the teen’s account was corroborated by surveillance footage.

“This was, fortunately for us, a rudimentary IED,” Beere said. “Had it used a little bit more skill and ingenuity, it would have caused a lot more damage and serious injuries.”

Gaines was arrested and booked into the Santa Rita Jail on suspicion of possessing a destructive device, a destructive device near a populated location, use of a bomb to destroy property and exploding bomb causing bodily injury, SF Gate reported, citing jail records.

He was being held on $3 million bond.