The killer is nicknamed the "Tommy Killer" after the rock opera Tommy (1975) by The Who. The killer glues his victims' eyes open, which reminded the authorities of the rock opera's recurring line, "See me, feel me, touch me."
This episode marks Reid's 24th birthday.
The ballad quoted by the unsub is "The Great Messenger of Mortality, or "A Dialogue betwixt Death and a Lady," which was originally printed on a broadside by J. Deacon sometime between 1683 and 1700.
The unsub is nicknamed the "Tommy" killer, after the rock opera of the same name, written by The Who. The previous episode was Won't Get Fooled Again (2005), titled after one of The Who's greatest hits.