Killer FedEx driver Tanner Horner snorted a line of cocaine when his attempt to strangle 7-year-old Athena Strand failed, before he beat her to death, a psychiatrist testified at his murder trial Wednesday. “He tried to kill her by breaking her neck. Then he choked her,” Dr. Eileen Ryan, a psychiatrist who heard Horner’s own description of his gruesome crimes, told the jury. “She was still alive after he choked her. He could hear her breathing. He did another line of coke,” Ryan continued,