The defendant’s son, Patrick Zamarripa, was working a bike patrol July 7 during a rally through downtown Dallas to protest the shootings of several black men by police. Near the march’s end, gunman Micah Johnson opened fire on police with a rifle, killing five officers, including Zamarripa. The Navy veteran died, leaving behind a girlfriend, two children, and his parents.

“I want justice for my son,” the elder Zamarripa told the Fort Worth Star-Telegram Monday. “He served three tours in Iraq, he protected his country, and he protected everybody. And he gave up his life doing that.”

The lawsuit claims BLM inspired Johnson to violence, because, it says, the group has crafted a divisive message that teaches followers they are in a “civil war between blacks and law enforcement, thereby calling for immediate violence and severe bodily injury or death” to police. The lawsuit also references a comment made by then-police Dallas Chief David Brown, who said Johnson’s goal that day was to kill white people, especially white officers. BLM has denounced Johnson’s actions.

There is no local BLM chapter in Dallas, and the group that organized the rally, the Next Generation Action Network, was not listed as a defendant in the suit; its leader has denied knowing Johnson. The suit listed 13 defendants, among them: the Nation of Islam, the Reverend Al Sharpton, the New Black Panthers Party, George Soros (who has reportedly donated money to BLM organizers), as well as several activists connected to BLM, including DeRay McKesson, who unsuccessfully ran for Baltimore mayor.

The lawsuit seeks $550 million in damages.

Johnson, who’d served in Afghanistan but returned home after being accused of sexual harassment, had expressed support for radical black-power groups, but even groups such as the People’s New Black Panther Party disavowed him, saying that though Johnson expressed interest in joining its ranks, he was turned away and blacklisted.