A 12-year-old boy accidentally hanged himself on a zip line near Redmond, Wash., Wednesday.
The Associated Press reports that first responders attempted to revive the boy but he was pronounced dead at the scene.
Investigators are trying to determine whether the boy's helmet chin strap or harness contributed to his death.
"At this point, it does appear to be an accident," a spokeswoman for the King County Sheriff's department told the AP.
The zip line, which had been professionally installed, was on the private property of the boy's family. It has since been removed.