The family of Ryan Mumm confirmed that he died on Sunday, a day after Snohomish County deputies found him wounded in Blue Stilly Park in north Snohomish County.
Deputies responded to the scene at about 8:30 p.m. on Saturday after receiving reports of a shooting, said Lt. Stephen Dittoe of the Snohomish County Sheriff's Office.
Mumm was treated at the scene before being rushed to Providence Hospital in Everett.
Witnesses said several vehicles fled the park just after the shooting and before deputies arrived. The suspect remains at large. No description was immediately available.
During the course of the investigation, deputies found a car at a local gas station that may be related to the shooting. The area was cordoned off with crime scene tape as detectives gathered evidence.
Officials said it is not yet clear exactly what led up to the shooting.
Mumm's mother, Kim Mumm, released a statement about her son.
"Cradled in the arms of the love of his family, Ryan Mumm passed away on July 15th 2012," the statement reads. "Ryan was a victim of a horrible and senseless tragedy. Although we could not save Ryan, he will be saving the lives of many people through his deep and generous act of love by organ donation. We will miss him forever and find comfort in the knowledge that we will be with him again one day."