Despite the severity of his wounds , Dobyns refused disability retirement and returned to duty within months of the shooting . For the next two decades , he conducted over 500 undercover operations , developing expertise in violent crime investigations , weapons and narcotics trafficking , gang infiltrations , home invasion burglary and murder-for-hire cases . He also served as an instructor at ATF 's National Academy and member of the Bureau 's Enhanced Undercover Program . He was repeatedly detailed to high-profile criminal and terrorism events including the " Rodney King " riots in Los Angeles , California , the Branch Davidian standoff in Waco , Texas , the Columbine High School massacre in Littleton , Colorado , and the Murrah Federal Building bombing in Oklahoma City , Oklahoma
Columbine High School massacre
Columbine High School massacre
Jay Dobyns