OAKLAND -- Six-year-old Adan Esparza had just climbed into his family's car on Sunday afternoon outside an East Oakland market when his father, standing outside the car, suddenly yelled to him: "Run!" In an instant, two robbers shot his father, and little Adan took off, turning back to see the assailants digging into his dying father's pockets.

The first-grader has since told relatives over and over what happened, not realizing that he never will see his father again.

Now, as police try to find the killers of Jose Esparza, his family is struggling to explain to Adan and his 11-year-old brother that their doting father is gone.

"I can't believe it," Maria Julia Carrillo, 39, said through tears Monday while surrounded by family and friends at her home, just blocks from where her husband of 13 years was gunned down outside El Pueblo Market at the corner of 103rd Avenue and International Boulevard.

"It's really hard," Carrillo said. "I don't know what I'm going to tell them. They're always going to be missing their dad. Who's going to guide them?"

As she spoke, Adan sat quietly nearby, playing a pocket video game.

Esparza and Adan had just left the market shortly before 1 p.m. Sunday where Esparza had cashed a $300 paycheck from his new job at a cheese factory in Hayward. Adan had hopped into the car and was waiting for his father to get in when the two men accosted him. Relatives say the assailants may have seen him with the cash.

Carrillo and her other son, 11, were just down the street buying churros, waiting for Esparza to pick them up. When Esparza didn't answer his cell phone, Carrillo and her son walked to El Pueblo and came across the crime scene, with officers everywhere.

Police have not released a description of the assailants.

Esparza may have resisted the robbers' demands because his family was hurting financially and needed all the money it could get, his family said. He had once vowed to his wife that if he were ever robbed, "He wouldn't give it up," said a nephew, Tony Da Silva, 17, of San Leandro.

"He was very happy that he was getting his salary," Carrillo said through a translator. "Prior to that, he didn't have a job, so he was glad he was providing for his family."

"The last thing he said, he told his son to run, and as he was running, he looked back and saw them searching his pockets and stuff," Da Silva said. The assailants fled with the money from the cashed check, an additional $500 in cash and Esparza's cell phone.

"He was always with his sons," Da Silva's sister, Stephanie Da Silva, 19, said as she paid her respects at a memorial of flowers and candles outside the market. "I don't know how the little one's going to take it. He doesn't really get that his dad is dead."

"This violence that's happening in our community must stop," Carrillo said. "It's destroying families, leaving sons without fathers and fathers without sons." She cited the case of Carlos Nava, 3, who was gunned down in East Oakland earlier this month. The boy's suspected killer, Lawrence Denard, appeared Monday in court but did not enter a plea.

Sergio Romero, 17, a nephew of Esparza, said his uncle was humble.

"He's the type of person - he didn't have a lot to give but if he had it, he would give it to you," Romero said. "What can I say? They took a great man out of this world."