First appearance of Dr. Sweets
Hodgins mentions the case of "that german guy" who posted an ad, looking for someone to eat. He is talking about Armin Meiwes, the "Rotenburg Cannibal"
Beth Grant (Lizbeth Harding) also appeared with David Boreanaz in "Angel: Rm w/a Vu" as the ghostly old woman haunting Cordelia's new apartment.
John Francis Daley had previously appeared in Kitchen Confidential (2005), one of whose sets was used in Two Bodies in the Lab (2006).
The hole in the sternum was already used in season 1 The Woman in the Garden except that time they were Salvadorian and this time they are white.