RICHMOND, Virginia (AP) — A gunman who opened fire minutes after a high school graduation in Richmond, Virginia, targeted an 18-year-old graduate he had a long-running dispute with, police said Wednesday.

Shawn Jackson, 18, and his father, Lorenzo Smith, 36, were both killed Tuesday in the gunfire, which sent hundreds fleeing in panic outside the state capital’s Altria Theater after the graduation ceremony for Huguenot High School. Five other people were wounded by gunfire, and at least 12 more suffered other injuries or were treated for anxiety due to the mayhem, according to police.

Richmond Interim Police Chief Rick Edwards said the shooting suspect, Amari Pollard, 19, knew Jackson and the two had been embroiled in a dispute for more than a year. Edwards said the nature of the dispute is still being investigated.

“This was targeted at one individual. … That’s what we know at this time,” Edwards said during a news conference Wednesday.

Pollard was arraigned Wednesday morning on two counts of second-degree murder, said Colette McEachin, Richmond’s top prosecutor. Pollard said he intends to hire an attorney, so the court continued the case until a hearing later this month, McEachin wrote in an email. Pollard was ordered held without bond. Court records did not immediately list an attorney who could speak on his behalf.

Jackson had just received his diploma at the graduation ceremony and had walked to a nearby park with his father to reunite with the rest of their family when the shooting started, said Tameeka Jackson-Smith, Jackson’s mother and Smith’s wife.

Edwards said police believe Pollard attended the graduation, then went outside, where he had some kind of “interaction” with Jackson, and then went to his car to retrieve a handgun. Other guns were also retrieved from the scene, Edwards said.

Edwards said authorities plan to trace the handgun. He said it was not immediately clear how it had been obtained by Pollard because at age 19, he would not have been able to buy a handgun himself from a licensed dealer.

A federal judge in Virginia ruled last month that a federal law banning licensed federal firearms dealers from selling handguns to young adults under 21 violates the Second Amendment and is unconstitutional. The Justice Department has filed a motion asking the judge to put any injunction he may order on hold until the government decides whether to appeal his ruling and until any appeal is decided.

No officers were injured amid the incident and no officers discharged their weapons, according to Edwards.