Identifying a psychopath is a complicated process involving hours of behavioural analysis and expert opinion.
However, a psychopath's sense of smell could be another piece of the puzzle in their identification.
The revelation comes after research looked into how well 79 non-criminal psychopaths could smell common aromas like coffee, fish and oranges.
The stronger their psychopathic traits - such as manipulation, an erratic lifestyle and callousness - the trickier they found it to distinguish between the odours.
The research speculates that this could be due to psychopaths typically having impaired functionality in the frontal parts of their brains.
It is the frontal lobe of the brain that aids planning, decision-making, social behaviour and processing smells.
The study concluded:
Our findings provide support for the premise that deficits in the front part of the brain may be a characteristic of non-criminal psychopaths.
Olfactory measures represent a potentially interesting marker for psychopathic traits, because performance expectancies are unclear in odour tests and may therefore be less susceptible to attempts to fake good or bad responses.
However, it is important to remember that a poor sense of smell - which can also occur in schizophrenia, Parkinson's and Alzheimer's disease - does not necessarily mean someone is a psychopath.