Season 1, Ep 3, Hannibal, Abigail returns home after waking up from her coma and sees the word "cannibals" painted on their garage door.
Then Abigail asks Will if a place is where her mom dies and hence expects to see a body outline in chalk; Will replies police only do a body outline if a person is injured and taken to hospital.
ABIGAIL: I was sort of expecting a body outline in chalk or tape.
WILL GRAHAM: They only do that if you’re still alive and taken to the hospital before they finish the crime scene.
I think it is logical for police to do this as they need to re-construct the crime scene but an injured person needs to be taken away soon thus they will draw a chalk outline.
But I think it is also possible to police to do a chalk outline for a deceased person as well; say they cannot finish re-constructing the crime scene before this dead body is taken away, they can do a chalk outline. Therefore, Will says is not entirely accurate.