RICHMOND -- Lileni Vazquez sat cross-legged on the lawn in front of a Curry Street home, watching mourners carry balloons and flowers into the parking lot of an apartment complex just across the street where her 16-year-old cousin, Ulysis Grijalva, was shot and killed Sunday night.

She struggled to make sense of why Grijalva would be targeted in a neighborhood where he was surrounded by friends and loved ones.

"He was the one that brought joy to the family," she said, talking about how she would see Grijalva at family parties and barbecues. "He was such a happy boy."

Grijalva's grandfather, Arturo Solis, sat nearby, speaking in Spanish about how his grandson would spend whole days with his grandparents, talking and playing blackjack for quarters.

"He was so loved," Solis said. "We're going to miss him forever."

Police said Monday the shooting of Grijalva may have been gang-related, but those who knew him well said he was not in a gang. Grijalva, a Richmond native, was shot to death about 9:30 p.m. in the 200 block of West MacDonald Avenue, said Richmond police Lt. Bisa French.

A man in his 20s who police have not identified is in custody in connection with the shooting, French said. As of Monday, police were still looking for another suspect.

The killing is Richmond's 13th homicide of 2012.

"He wanted to get a scholarship (to college) and play pro football," Vazquez said of Grijalva, a varsity offensive lineman

for the Kennedy High School football team. "He said, 'This year we're gonna make it to the playoffs.'"

"He would always make jokes when they lost. He'd say, 'We'll get them next time.' He was so positive."

The team was due to begin two-a-day practices Monday, Vazquez said, but instead, they traveled together to Grijalva's home to pay tribute to their teammate.

Earlier, at the school, head coach Mack Carminer remembered Grijalva, who was about to start his junior year.

"He

was a phenomenal kid. Always had a smile on his face," Carminer said of the boy, who wore jersey No. 64 on the field. "He didn't live a hectic lifestyle and wasn't involved in gangs. He was respectful and a good son to his parents."

The team's quarterback, junior Roman Espinoza, attempted to address reporters about his friend but instead broke down in tears. Grief counselors were on hand at the school to meet with students.

The teens, Carminer said, were close.

"My kids are distraught about what is going on. Today will be a day of counseling and mourning," said Carminer, who's been head coach at the school since 2011. "They're doing the best they can with losing a surrogate family member. That's what we are. A family."

West Contra Costa Unified School District school board President Charles Ramsey called the killing a tragedy.

Three years ago, the district had a record 11 students killed during one school year, Ramsey said.

"Once again, an innocent child -- a 16-year-old -- loses their life in a senseless killing," Ramsey said. "Richmond is dangerous. I'm concerned."

The killing took place on the western edge of Richmond's Iron Triangle, a neighborhood that is the site of much of the city's violence. However, Vazquez, who lives just around the corner from Grijalva, said violence wasn't part of their family's experience.

"People ask if it's a bad neighborhood," she said. "I tell them, I don't know. We don't make any trouble. (Ulysis) hung around with everybody."

Contact Natalie Neysa Alund at 510-293-2469. Follow her at Twitter.com/nataliealund. Contact Daniel M. Jimenez at 510-262-2728. Follow him at Twitter.com/DMJreports.