SAN BERNARDINO ( — Family and friends are mourning an 8-year-old boy who was killed in the crossfire of an apparent murder-suicide plot that was carried out inside of a classroom at an elementary school in San Bernardino.

FULL COVERAGE: San Bernardino School Shooting | Photos

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Family members say Jonathan Martinez – who was struck by gunfire Monday morning as he hid behind his teacher, Karen Elaine Smith, who was the target of her estranged husband, Cedric Anderson – suffered from Williams syndrome, a genetic heart condition.

Anderson fired six rounds, subsequently killing Smith and wounding Martinez and another male student at North Park Elementary School.

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Paramedics airlifted the boys to Loma Linda University Medical Center, where Martinez later died.

The other 9-year-old boy remains listed in stable condition. His identity has not been released.

A GoFundMe account has been set up to assist the Martinez family. To donate, click here.

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A candlelight vigil for Martinez was set to be held at North Park tonight at 7 p.m.