A 16-year-old Frisco teen in custody Tuesday told officers he simply wanted to kill someone, and the 14-year-old boy he shot Saturday night was a random target, police said. The student from Frisco High School, who was not identified because he is a juvenile, not only confessed to shooting the boy as he opened his front door, but also said that on Thursday, he shot at a man as he walked his dog, police said. He is not the same teen who was originally questioned in the shooting Saturday. That boy, 15, has been released and won't be charged, said...