LAKE BALBOA (CBSLA.com) — A family is heartbroken after a 17-year-old boy was fatally stabbed at a party in Lake Balboa over the weekend.

Roberto Rizo, a student at Canoga Park High School, was attacked early Sunday morning at a home in the 15700 block of Sherman Way.

A resident at the house told CBS2’s Cristy Fajardo that his roommate met a girl, who invited hundreds of strangers to the backyard get-together.

Police said a fight broke out and a group of assailants confronted Rizo. One of the suspects stabbed him with a knife multiple times.

The teenager was taken to the hospital where he underwent emergency surgery, but died a day later from his injuries.

Detectives don’t believe the stabbing was gang-related, but are unsure of the motive because no witnesses have come forward.

Cassandra Anguiano, Rizo’s sister-in-law, said, “I wish they would help us out…help us find out who did it. They’re walking out there like nothing happened while our whole family is crying…missing (him).”

Anguiano said the victim was an avid sports fan and a doting uncle who had plans to join the Marines after high school.

“He was a great kid. He didn’t deserve (to die),” she said.

Police encourage anyone with information about the stabbing to call West Valley Homicide detectives at (818) 374-7720.

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