Forensic Files S08 E26 Letter Perfect

"No Witnesses. No Leads. No Problem."

A healthy young man dies mysteriously in his sleep. There are no signs of trauma or injury, but toxicology tests reveal a lethal dose of lidocaine in his blood. Investigators find a suicide note, and presume he killed himself until a forensic linguist examines the note and determines that what the victim said is less important than how he said it.