GOLETA, Calif. — Richard Martinez grew up around guns, shooting birds out of the fruit trees on his family’s farm. He later served as a military police officer in the U.S. Army before going on to become a criminal defense lawyer, at times representing the young and the violent.

Now, Martinez is a grieving father.

He’s asking members of Congress to stop calling him to offer condolences but nothing more for the death of his only child, Christopher Michaels-Martinez, who was killed in the rampage Friday in Santa Barbara, Calif.

“I don’t care about your sympathy. I don’t give a s— that you feel sorry for me,” Richard Martinez said during an extensive interview, his face flushed as tears rolled down his face. “Get to work and do something. I’ll tell the president the same thing if he calls me. Getting a call from a politician doesn’t impress me.”

Saying “we are all to blame” for the death of his 20-year-old son, Martinez urged the public to join him in demanding “immediate action” from members of Congress and President Barack Obama to curb gun violence by passing stricter gun-control laws.

“Today, I’m going to ask every person I can find to send a postcard to every politician they can think of with three words on it: Not one more,” he said Tuesday. “People are looking for something to do. I’m asking people to stand up for something. Enough is enough.”

Martinez is the latest tragic figure to raise the mantle of gun control. Previous massacres and spasms of violence have produced urgent calls for new restrictions.

But these poignant appeals – most recently from former Arizona congresswoman Gabrielle Giffords, who survived a 2011 assassination attempt, and the Sandy Hook families whose 20 children were gunned down in their Newtown, Conn. elementary school in late 2012 – have failed to translate into action by Washington. Nor have they significantly changed public opinion about further regulation of weapons.

Martinez vowed that he’s not going away. He said his training as a lawyer explains, in part, why he has not retreated from public view as many parents do after such a tragedy.

“We are tough people,” Martinez said of himself and Christopher’s mother, Caryn Johnson Michaels, a deputy district attorney in San Luis Obispo. (The couple separated when Christopher was young.) “Caryn was in charge of the sex crime unit. We fight.”

The families of the other victims remained largely out of public view ahead of the memorial service Tuesday afternoon at the University of California at Santa Barbara. Two of the victims, Veronika Weiss and Katie Cooper, were members of UCSB’s Tri Delta sorority, and on Tuesday, the sorority issued a statement in response to their deaths.

Martinez, 60, vaulted into the spotlight Saturday when he crashed a Santa Barbara County Sheriff’s Office news conference at which deputies spelled out the details of the knifing and shooting attacks by Elliot Rodger, the 22-year-old who killed six people before shooting himself.

Martinez said he is consulting with experts to help develop a clear message and a specific course of action that the public can undertake with the aim of preventing similar tragedies in the future.

“There’s no playbook for this. We don’t know what we are doing,” he said. “I just know I have to keep fighting until something changes. The most precious thing in the world has been taken from me. What else can I do?”