Christopher Martinez, 20, and five other students were shot to death while celebrating the end of school in the college town of Isla Vista, California.
Courtesy Richard Martinez
Richard Martinez with a young Christopher. Martinez has made it his mission to fight gun violence.
Courtesy Richard Martinez
Martinez became an activist when he took to the podium at a press conference intended for law officers to talk about the Isla Vista shootings.
Courtesy Richard Martinez
Christopher Martinez intended to become a lawyer, following in his father's footsteps.
Courtesy Richard Martinez
Martinez, a criminal defense attorney, hasn't worked in court in the year since his son's death. Instead, he has traveled to speak against gun violence.
Courtesy Richard Martinez
The gunman who killed Christopher had a history of mental issues. Martinez thinks it should have been harder for him to get a gun.
Courtesy Richard Martinez
Martinez has taken his case around the United States.
Courtesy Everytown for Gun Safety
Martinez learned about social media on the fly, and urged students to hashtag the slogan "Not One More."
Courtesy Everytown for Gun Safety
Martinez says he will continue working to keep guns out of the hands of the dangerous and mentally ill.