A jury found Colin Gray, the father of an accused Georgia high school shooter, guilty on all 27 counts Tuesday, including second-degree murder. Last week Gray testified in his own defense that he never noticied any signs of trouble with his son,

A man has been convicted of murder and manslaughter after giving a semiautomatic, assault-style rifle to his teenage son, who is accused of using it to kill two high students and two teachers.

The jury deliberated only about two hours before concluding that the father, Colin Gray, 54, was guilty of more than two dozen charges, including second-degree murder and involuntary manslaughter, ste...