In a statement, his family said he was found dead in his car on Friday, Dec. 3. The Cook County Medical Examiner said he died from multiple gunshot wounds and ruled his death a homicide.
Family described Martins as "a community leader who fought for peace and justice."
He graduated from Northern Illinois University, and served as an assistant dean at a south suburban school and a paraprofessional for a CPS elementary school in East Side.
He also lobbied for violence prevention programs and policies, family said.
Police have not commented on the circumstances of Martins' death.