PHILADELPHIA — It’s been nearly a year since Christopher Hinkle was beaten to death inside a Philadelphia jail cell, but his family says it knows little more about his last moments than it did when first told of his death. “I don’t know anything,” said his mother, Diana Lawhon. “I know from what I saw in the hospital, from what the doctors told me, and from the autopsy report. But I don’t know what happened in the jail. I don’t know what happened in that cell. I don’t know why he was put in with somebody who was in on a violent crime when [her son] was in on a drug charge.” Lawhon, of the Poco…