The parents of Daniel Rohrbough had alleged that a Denver tactical officer mistakenly shot their son during the melee, but an independent review released by the El Paso County Sheriff cleared the officer.
El Paso County Sheriff John Anderson conducted the investigation at the request of Jefferson County Sheriff John Stone, who had jurisdiction in the massive police response to the April 20, 1999 shooting rampage in Littleton, a Denver suburb.
The new report states the murder of Rohrbough "was undeniably caused by gunman Eric Harris beyond any reasonable doubt. If Eric Harris were alive today, there exists overwhelming probable cause to arrest him for the murder of Daniel Rohrbough."
Harris and Dylan Klebold opened fire at Columbine, killing a dozen students and teacher Dave Sanders before taking their own lives. Rohrbough was shot and killed outside the school before any officers arrived, the investigation concluded.
Rohrbough's parents had questioned earlier reports by the Jefferson County Sheriff's office and alleged in a federal lawsuit that a Denver officer fired the fatal shot. They had no immediate comment.
The El Paso County investigators interviewed more than 140 witnesses as well as the results of ballistic tests, other lab work, and crime scene reconstructions during the four-month-long review.
Celebrity Couples of 2014 [PHOTOS]