"When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth." Sherlock Holmes
Scottish software developers have developed a program to help police consider all the possibilities in the investigation of suspicious deaths.
'Sherlock Holmes' is designed to highlight less obvious lines of inquiry that detectives might overlook.
"It takes an overview of all the available evidence and then speculates on what might have happened," developer Jeroen Keppens, of Edinburgh's Joseph Bell Center for Forensic Statistics and Legal Reasoning, told New Scientist.
According to Keppens, the package could help prevent miscarriages of justice. It's human nature to latch onto a particular theory for a suspicious death and then attempt to confirm it, possibility neglecting other possible explanations.
A knowledge base within the program contains data of various causes of death and evidence that either supports or contradicts a particular explanation for a death. Investigators enter data into the program, which applies this database to indicate the likelihodd of each scenario. Forensic evidence, medical reports and eyewitness accounts can all be fed into the system. In this way, the program helps police consider all possibilities rather than leaping to an obvious (and perhaps false) conclusion.
For example, doctors rule that a death was caused by bleeding in the skull, the program would consider all the ways this might have occurred and calculates their relative likelihood.
Keppens said: "It could be accidental or alcohol induced. In the elderly and with infants, falling over could be the cause - or it could be caused by a blow to the head."
The system is capable of considering overlapping possibilities. For example, if the deceased was an old man and an alcoholic, homicide would still be considered as a possible cause of death.
Independent experts give the idea a cautious welcome.
David Holmes, director of Manchester Metropolitan University's Forensic Research Group, told New Scientist that the system could prove useful in police investigation. However he did express some reservations.
"What worries me is the sheer volume of information you'd be expected to put in," he said.
The software is still at the prototype stage but developers at the Joseph Bell Center could be in use in real police investigations within the next two years. ®