Differences between past & present: how evidence is collected, documented, and analyzed
Lack Of Tools
Furthermore, there was a lack of adequate tools to gather evidence during crime scene documentation, detrimentally affecting visual evidence preservation essential for presentation of a case in court many years later. Before the recent developments in the past 20 years, there were not yet any 35mm cameras, automated color film processing and high resolution of 25-100 ISO film that are now currently widely available for easy documentation of evidence.
For example, prior to the invention of the magnetic fingerprint brush by Herbert MacDonnell in 1961, there was much difficulty in collecting fingerprints. This tool was perfect for developing fingerprints at a crime scene as magnetic fingerprint powder adhering to the wand can be easily brushed onto fingerprints without physical contact. There would no longer be any danger of brushing the prints away or overdeveloping them. (Schiro G., 2000)
Manual VS Automation
In the past, manual searches for fingerprint identification was extremely time consuming. With the introduction of the computerized database Automated Fingerprint Identification System (AFIS) in 1996 that automatically compares fingerprints from a crime scene to a databank of known fingerprints electronically, time and effort of crime scene investigators are greatly conserved. (Refer to timeline)
Better Techniques
Poor analysis of body fluids found in a crime scene was one of the main problems plaguing crime scene investigators of the past. Large amounts of blood evidence were required just for identification of ABO blood types and certain genetic markers, which might not be effective in narrowing down the vast list of suspects. Analysis of blood is also not effective as it is extremely susceptible to environmental degradation. Comparatively, DNA analysis techniques developed from 1986 into the 21st century have ensured extreme accuracy down to the most individual detail, as DNA is unique for every individual. Also, very small amounts are needed as PCR techniques can amplify these into suitable amounts for analysis. DNA does not degrade over time and are timeless evidence aiding investigators in identifying the right suspect.
Advancement in Technology
In the past, there were no computerized databases for storage of information regarding guns, fingerprints, DNA or criminal profiles. Thus, there were extremely low success rates of identifying suspects. In contrast, there are now multiple databases IAFIS (for fingerprints), NIDIS (for DNA), Drugfire and IBIS (for ballistics) that can even share data between states. For example, a DNA profile from crime scene body fluids can be compared to a database of DNA profiles to identify a suspect. Several states in the United States are now routinely making "hits" from past unsolved cases to new DNA data currently collected from convicts.
Bare hands VS Protective Gears
Before major advancements occurred to bring forensic science to its current stage of development, there was a lack of inexpensive and widely available protective gear such as gloves, the first line of defense in protecting crime scene detectives from bio-hazardous material like HIV and infectious Hepatitis viruses. Protective gloves and their usage will likely not change much in the future, but other protective gear will definitely become cheaper and more widely utilized as new biohazards evolve or regulation of crime scene investigations become stricter.