My mother worked for the local Prosecutor’s Office years ago in New Jersey. [same as District Attorney elsewhere].
When she was in the child abuse unit, a new employee came in. My mother was showing her around with her co-worker, and the new employee said, “Well, there’s no such thing as a perfect crime!”
My mother looked at her co-worker and said wryly, “The graveyard is full of them.”
Homicide dept there had a big sign on the door: “Our day begins where your day ends”. Unrelated I just like it.