S13·E11 Stranger in the Night

In 1991, Dorothy Donovan was murdered in her Dover, DE home and police are skeptical when her son Charles Holden stated that she was murdered by a hitchhiker he had picked up. Their suspicions were heightened when he refused to take a polygraph test and they turned to forensic science. Would the blood and fingerprint evidence at the crime scene support Charles' story or prove his guilt?