ABSTRACT
It is a recognized fact that in many cases no witnesses are available and all the evidence is circumstantial. In such cases science may help in a way which is beyond the range of any possible evidence depending upon the personal observation of the police or of other witnesses. In some cases it may supply vital evidence against the guilty party, or in others definite proof of innocence where guilt was suspected. It may give certainty amidst apparently conflicting stories from witnesses, and at the very least it may provide a means of reconstructing the crime and thus saving an immense amount of unnecessary work for the investigating officer, by eliminating lines of enquiry which would otherwise require attention and pointing to those which are most likely to be fruitful (Home Office, 1949: 3).
