IT WAS once again the DNA wot done it. An FBI affadavit says that DNA found on the knife investigators believe was used in the brutal slaying of American University professor Sue Marcum has been linked to a Mexican man. She was murdered last October, which initially looked like a botched burglary.According to The Washington Post the complaint charges yoga instructor Jorge Landeros, 41, with unlawful flight. Marcum, 52, a popular accounting professor, when she met Landeros about six years ago when he
