LOS ANGELES, California (CNN) -- Jamiel Shaw Sr. thought he'd see a "monster" in court when he turned up to see the gang member accused of gunning down his son just yards from his home.
Jamiel Shaw Sr. says he wants to bridge the gap between blacks and Latinos in Los Angeles. "I owe it to Jas."
But instead, the father said, the teenager accused of the killing looked just like a "normal" youngster. Pedro Espinoza, 19, who police say is a member of the notorious 18th Street Gang in Los Angeles, made a brief court appearance Tuesday.
Anita Shaw, who was stationed in Iraq for the U.S. Army when her son, Jamiel Jr., was killed, also was there yesterday. She said she was filled with anger when she saw Espinoza.
"I wanted to get up in his face and say, 'How dare you kill my baby! How dare you kill anybody,'" she told CNN just hours after the court appearance.
Police say that shortly after 8:30 p.m. on March 2, Espinoza pulled up in a car and asked Shaw if he was in a gang. Shaw didn't have time to tell him "no"; he was gunned down before he could answer, according to police.
The father says he can't forgive the man who allegedly killed his son. But he says his son's death has given him a new calling: to try to bridge the divide between blacks and Latinos in Los Angeles. Watch dad describe why blacks, Latinos must unite »
"I figure something good has to come out of this," he said.
Espinoza is charged in the killing and prosecutors say he could face the death penalty if convicted.
Espinoza had been released from jail a day before the shooting. He had been jailed for resisting a police officer and brandishing a firearm. Authorities say Espinoza had served just over half his sentence before he was released.
But he should never have been in the country.
According to immigration officials, Espinoza was in the country illegally. Immigration officials say local law enforcement had never referred Espinoza to them because when he was booked, he claimed he was from California.
"It's sort of hard to understand, especially now that we know that it all could have been avoided. It was so avoidable," Jamiel Shaw Sr. said.
In an interview with CNN over the weekend, the dad spoke gently, softly about his boy. At times, tears streamed down his face.
"We didn't ask for this. We were just sort of thrown in this," he said.
How does the father find the strength to continue?
"It's bigger than me. It's bigger than Jas now," he said, referring to his son by his nickname. "It's important because I feel like I owe it to Jas." How you can help
Shaw, a junior, was a standout running back and sprinter at Los Angeles High School who did well in school and stayed out of trouble. Among the schools that recruited him was Stanford University.
The father said his son was friends with Latinos, whites, blacks -- everybody. In fact, one of Jamiel's best friends was a Latino. Not speaking out for unity, the father said, would make him a "hypocrite."
"I figure it's up to me to make a stand," he said. Watch tearful dad recall when "time just stopped" »
Mayor Antonio Villaraigosa on Saturday walked the same street as Jamiel did on the night he was gunned down. He was flanked by dozens of Jamiel's friends and family. Almost three years ago, the mayor had planted a tree on the same street with Jamiel and his father as part of Los Angeles' "Million Trees" initiative.
On this day, the mayor presented a "Tree of Life" plaque at the same spot.
"Jamiel Shaw stood for everything that's right in this city, for the talent and the drive in all of our children, for the endless possibility that they carry inside of them," the mayor said.
Jeff Carr, who heads the mayor's Gang Reduction and Youth Development program, says 90 percent of LA's gang-related crime is "primarily black on black and brown on brown," and not across racial lines.
"But I do think whenever there is a cross-racial killing like this, it does cause a lot of concern, and it's certainly something we have to address and look at," he said.
Anita Shaw said her "big wish" is for parents to be more involved in their children's lives to keep them from straying into a life of crime.
"I believe if enough parents -- if enough mothers get involved -- it can stop," she said.
As for Jamiel's father, the pain of the last month has been too much to bear.
"My mind is just not processing that he's gone," he said. "It's hard to move on because we can't even accept the fact he's gone. But in the meantime, we have to make something good out of this." E-mail to a friend
CNN's Kara Finnstrom and Michael Cary contributed to this report.