Has there been any research in criminology, psychology, or some other related field? Something that shows a correlation between the everyday facial expression someone wears on their face, and whether they have murdered someone? In the absence of research, is there at least an expert opinion?
The field of trying to work out a person's personality from their face is called Physiognomy.
It is now being revived again as some new research indicates that people's faces can indicate such traits as trustworthiness, social dominance and aggression. The latter trait seems to be determined by the level of the hormone testosterone during puberty, which affects the ratio between the height and width of the face - aggressive individuals are found to have wider faces.
There are references there about detecting people's political preferences too.
I would expect (without evidence) that detecting criminality would be swamped more by factors of clothes, cosmetics (including hairstyles and tattoos) and racial profiling than actual facial characteristics.