Ms Dalley, one of the United States' first designated crime scene agents, is a specialist in crime scene reconstruction and event analysis.
She spoke yesterday at a forensic biology summer school class at the University of Otago After 20 years in the field, most recently as a special agent with the Oklahoma State Bureau of Investigation's eastern regional office, Ms Dalley has since 2009 been a partner in a forensic education and consulting company, where she works for lawyers and trains police and others in crime scene analysis.
Putting a crime scene back together was something that took a significantly longer time than it took to commit the crime, she said.
There was a very specific methodology around reconstructing the scene and all hypotheses had to be tested against evidence available.
The seven steps to analysing a crime event were to collect data, establish specific event segments, decide which were related to each other, sequence the event segments and establish a flow for the event, consider all possible sequences, work out the final sequence, and flow chart the incident.
It was about using the science available to decide if hypotheses were credible.
"Crime scenes beg questions. If we are to answer them, we can bring some measure of justice, even if that justice is just to stop one person doing more damage."
Asked how she dealt with bloodied murder scenes, Ms Dalley said the human body was amazing and putting it back together in order to establish how it was broken was a fascinating task, and something completely separate to dealing with the emotions of such an event.
