(CHICAGO) Activists who have recently protested alleged brutality by Chicago police gathered to demand action in the killing of the 19-year-old son of a police officer.

Arshell Dennis was gunned down early Sunday as he stood on the porch of his home with a 20-year-old friend. Dennis died hours before he was leave for New York’s St. John’s University for the start of his junior year.

Activist Ja’Mal Green said he and other activists “want this killer to be brought to justice.”

Green was arrested last month for allegedly striking a police officer and trying to disarm another during a protest of fatal shootings by police.

Police spokesman Anthony Guglielmi says the victim’s father and Superintendent Eddie Johnson once worked together as patrol officers. He said Dennis’ death is being investigated as a case of mistaken identity.

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