Friends and family met Sunday night at Hughes and Norwich Avenues near the canal where his body was discovered.
In October, investigators arrested his roommate Lawrence Madrid for accessory to murder and Madrid's 17-year-old girlfriend for murder.
Police say they mutilated Bonboster's body, burned it and dumped part of it in the canal.
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His brother says this is their way to keep his memory alive and grow closer to one another in the midst of tragedy.
"As tragic as this has been, it's brought a lot of people together. You know. A lot of different families. We're out here. It's one of the many things. Just remember him. Just feel closer to him any way we can," said Nathaniel Rodriguez, Bomboster's brother.
"Because of Sergio, we have gathered here. This is two families he brought together. Because of Sergio, we have gathered here. One huge family. Tip of the iceberg on that," said Mona Esparza, Bomboster's mother.
Family and friends of Sergio Bonboster have been closely following the court cases underway for the two people accused of killing him.
They say they hope the 17-year-old girl accused in his death will eventually be tried as an adult.