UPDATED 06/14/11 9:19 a.m.

CHICAGO (CBS) — A West Humboldt Park neighborhood boy is dead, gunned down overnight as he celebrated his 15th birthday.

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As WBBM Newsradio 780’s Regine Schlesinger reports, Jovany Diaz was celebrating with a 19-year-old friend down the block from his home in the 4300 block of West Hirsch Street.

Suddenly, someone came from across the street and opened fire, killing Diaz and wounding the older boy in the hand.

Diaz was pronounced dead at Mount Sinai Hospital at 10:46 p.m., according to the medical examiner’s office.

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He was shot in the chest, police News Affairs Officer Ronald Gaines said.

Diaz was a student at Amundsen High School, 5110 N. Damen Ave.

Police say they only have a sketchy description of a gray or silver getaway car. They say the motive for the killing is unknown.

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The Sun-Times Media Wire contributed to this report.