How human element involved in various aspects of forensic work?
In lots of ways, for good and for bad.
Some of the more positive ways might be the development of empathy and understanding. This can make the forensic psychologist much more discerning in the evaluation of offenders.
Equivalently, less beneficial human elements include what are termed mental heuristics. These are like mental shortcuts the brain takes and can often steer our reasoning in the wrong direction. This and cognitive biases are always something to be careful of as they can influence our perspectives of offenders.