Colt Gray, 16, had pleaded guilty to murder and other charges. Judge Nicholas Primm, who also sentenced Colt Gray, was blunt in addressing the elder Gray: “It is clear you failed as a parent.” Prosecutors said Colin Gray missed red flagsProsecutors said Colin Gray gave his son the rifle as a Christmas gift along with ammunition, a gun sight and other shooting accessories. An investigator testified that Colt Gray carried the semiautomatic rifle onto the school bus with the barrel sticking out and wrapped in poster board. Like Colin Gray, they were unaware of their son’s plans but had gifted him a gun before the shooting.