A teenager has pleaded guilty to the triple murder of a 16-year-old girl and her parents after he shot the victims dead then went on the run when he was caught in bed with the girl. Mauricio Johnson pleaded guilty on Tuesday to three counts of first-degree murder and admitted to three special allegations of using a firearm in the killings of Shelly Moon, her mother Margarett Moon and her mother’s boyfriend Nikki Metcalf back in February, according to the Humboldt County District Attorney’s Office. Johnson, who was 18 at the time of the killings, had been hanging out with...