S14, E9: A middle-aged man, Gideon Blake, drops dead in an Oyster Bar. Detective Green detects the smell of bitter almonds, indicating cyanide poisoning. His lunch date, a pediatric oncologist named Bethany Allison, arrives after Blake's been taken away. The cyanide came from the hot sauce, which he brought himself. Blake had a strange profession. He "talked" to the dead and people paid him a hefty sum for his services. Briscoe and Green realize there could be many disgruntled former clients but discover his prints match a guy the Feds have been looking for, named John Wayne Mapes. Mapes/Blake bilked doctors out of millions of dollars and Dr. Allison is on his list.