S1·E16 The Adventure of the Judas Tree

The Queens investigate when a wealthy industrialist and war profiteer is stabbed to death with a Chinese ceremonial dagger and then dragged out of his house and hung from a tree with a crown of thorns placed on his head. Just like one Judas Iscariot. As usual, plenty of suspects abound and when it's discovered that the victim was dying of acute lymphoma the plot only thickens.