CHULA VISTA, Calif. – Family and friends came together Monday to mourn Maximilian “Max” Mendoza, the 12-year-old boy shot and killed this weekend at a Chula Vista condominium complex.

“Everybody loves his smile,” said his mother, Aida Mendoza. “He was such a good-hearted boy.”

The shooting happened about 9 a.m. Saturday at the Woodland Hills Condominium Complex on Telegraph Canyon Road, Chula Vista police Lt. Dan Peak said in a news release Sunday. Mendoza was located on the ground in the area of the complex with one visible gunshot wound, according to police.

Police detained a 15-year-old who they say “was a companion to the victim and is related to the investigation,” but the person was released to his family by investigators, Peak said.

Circumstances of the shooting are still under investigation.

Those that gathered Monday remembered Max as being funny, outgoing and protective of his four sisters, both older and younger.

“Even though he was only 12, you would talk to him and you would feel like you were talking to someone your age,” sister Macy Mendoza said. “He was so mature for his age. He was so wise beyond his years.”

She continues: “He always looked out for them at school, he’d be the one to pick them up from their classes and then walk over here. Even though he was four years younger than me, he’d be like, ‘Any guy gets near you, I’m going to deal with them.’”

While the family waits for answers, loved ones are joining them in paying respects to Max.

“They’re not alone in what they’re going through right now,” one of Max’s friends told FOX 5.

For now, they’re cherishing a small piece of Max in his dog “Boy,” who he’d once rescued from the streets.

“That was Max’s best friend,” Macy said.

A GoFundMe campaign has been set up to help with funeral costs.