Richard Martinez, the father of 20-year-old Christopher Michaels-Martinez, one of six killed in the Isla Vista, Calif., shooting rampage, spoke to the media Saturday. Martinez expressed his frustration with “irresponsible politicians and the NRA” on gun-control laws. (Reuters)

Richard Martinez, the father of 20-year-old Christopher Michaels-Martinez, one of six killed in the Isla Vista, Calif., shooting rampage, spoke to the media Saturday. Martinez expressed his frustration with “irresponsible politicians and the NRA” on gun-control laws. (Reuters)

— 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. “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 that “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 Obama to curb gun violence by passing stricter gun-

control laws.

1 of 67 Full Screen Autoplay Close May 26, 2014 May 25, 2014 May 24, 2014 May 23, 2014 Skip Ad × After the shooting rampage near University of California at Santa Barbara View Photos Santa Barbara reacts to Friday’s rampage. Caption The university and nearby Isla Vista, Calif., are mourning the victims of a 22-year-old student who stabbed three people in his apartment and fatally shot three others on the streets of the community. The shooter was found dead in his car. The mass killing has rekindled a long-simmering debate about gun control and mental health care in the country. Buy Photo Wait 1 second to continue.

“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 in Tucson, 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.”

At a memorial service organized by the University of California at Santa Barbara later in the day, Martinez was the only parent who spoke, but he also read statements from the parents of David Wang and James Hong, both computer-engineering majors.

For two hours leading up to the service, nearly 20,000 students, faculty, college alumni, local political figures and neighbors poured into the university’s soccer stadium. As the UCSB Young Artist String Quartet played, the stadium’s 17,000 seats filled and several thousand additional people, mostly students, sat on the grass field.

A dozen or more people at the venue wore orange vests with a sign that said “counselor” so that people who needed help could easily reach out and get it.

“It’s time to stop the gun violence. Our children deserve a land free from fear,” Martinez read from the statement from the Wang family, which went on to say, “Let us pray for all the people who lost their loved ones, including the family of the killer.”

Hong’s family asked Martinez to read a statement where the father recounted a dream he said he had the night before. “I saw my son in a dream last night. . . . [He said] my time at UCSB was the happiest time of my life. . . . I wanted to stay here forever with everyone. I know there are great injustices in the world and policies that could be improved. I can’t help with this anymore, but you can.”

Martinez wrapped up the statements from parents, asking the crowd to stand and shout “so loud they will hear you in Washington. Say it with me, ‘Not one more!’ The stadium thundered as the members of the crowd repeatedly shouted, clapped and stamped their feet on the metal bleachers. He repeated his call for people to send postcards to politicians but acknowledged that a Twitter ­campaign using the hashtag ­#NotOneMore might be more in keeping with the college crowd.

Janet Napolitano, the University of California president and former secretary of homeland security, called the shooting an “unfathomable tragedy” and encouraged the crowd to remember and celebrate the unique qualities of each of the students who were killed.

“All died much too young,” Napolitano said. “It’s important that we don’t let the arithmetic of this tragedy define them. Their individuality should not be obscured.”

A male student a cappella group, called BFOM (Brothas From Otha Mothas), sang a version of Billy Joel’s “And So It Goes” as everyone left the stadium after the service.

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

“Words will never be able to express the pain and sorrow in our hearts from experiencing the loss of our two beautiful sisters,” the sorority said. It added: “In the wake of this tragedy, we are committed to appreciating the value of life and to emulating the amazing attributes that Veronika and Katie shared so generously with us. We are grateful for and hold close to heart those who survived on Friday, including one of our own.”

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.

After the news conference, Martinez told reporters to train their cameras on him as he delivered a biting, 80-second speech attacking “craven” politicians and the National Rifle Association.

While Martinez said he is angered by the public’s willingness to accept mass murder as a way of life in America, he said he is not mad at Rodger’s parents.

“As bad as I feel about this, at least people come up to me and say, ‘I’m so sorry for you,’ ” he said. “Who will say that to them? No one is going to say that.”

Martinez said he hopes to meet with Rodger’s father, Peter Rodger, a Hollywood director and photographer, and enlist him in his fight to change gun laws. Peter Rodger and his attorney did not respond to a request for interviews.

“I’ve been told that the shooter’s father has said he wanted to devote his life to making sure that doesn’t happen again. I share that with him,” Martinez said. “He’s a father. I’m a father. He loved his son. I love my son. His son died. My son died.”

Martinez also said he is not angry with either the mental-health system or the sheriff’s deputies, who in April visited Elliot Rodger’s apartment after his family notified them, concerned about dark, brooding videos he had posted on YouTube.

The videos didn’t threaten violence, however, and Rodger was able to convince the deputies that he was depressed but neither suicidal nor homicidal, so they did not search his apartment, where he had already stockpiled an arsenal of weapons, including three semiautomatic handguns.

Martinez said that as a criminal-defense lawyer, he has seen the system from the inside and knows how difficult it is for parents to get help for their adult children when they are mentally ill.

He said he also recognizes that police have too few powers to intervene because the mentally ill cannot be involuntarily committed unless they prove to be an immediate threat to themselves or others.

“They don’t have the tools they need,” he said. “I don’t have the answers, but we should ask them what they need and we should give it to them. It’s a lack of will to find solutions. That’s what I’m upset about. This is a problem that can be solved.”

Martinez reserved his anger for the NRA, saying he has no understanding for the group’s position on automatic and semiautomatic weapons after a series of mass murders involving such weapons.

“I’m angry with the leadership of the NRA who always want to characterize this as if it’s a lone madman. That it’s an act of nature we have to tolerate,” he said. “I am angered by how they have worked to normalize this.”

The NRA did not respond to requests for comment.

“I understand this is a complicated problem. I have friends who are in the NRA. I grew up on a farm. I hunted. I killed animals. I understand guns,” Martinez said. “But assault rifles and semiautomatic weapons? There is no need for those except in war.”

He said his son — whom he described as “brave,” “competitive” and “extremely kind” — was also interested in guns but did not own any. He played paintball, expressed a desire to go to a shooting range and thought about following in the footsteps of his father by enlisting in the Army before college. An English major at UCSB, he planned to go to London next year and to law school after graduation, according to his father.

“He was very physically adventurous,” Martinez said. “He loved to argue. That’s probably why he wanted to become a lawyer, like his parents.”

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?”

Alice Crites and Julie Tate in Washington contributed to this report.