When Humphrey discusses the case with Camille on his porch, his shirt is buttoned wrongly. In the long shot it's higher on his right. But when he sits down it's suddenly higher on his left.
When Fidel first shows the body to the team, he says that the knife, still in the victim's back, has been wiped clean of prints. The lifting of fingerprints from a weapon is always done in a laboratory, not at the crime scene. Furthermore, it is clear that there is no fingerprint powder on the handle of the knife.