The modern-day detective has access to tools and techniques Sherlock Holmes could have only dreamed of. Who could have imagined, just 25 years ago, of putting a name to a fingerprint simply by running it through a computer, or identifying a rapist through his own body fluid?
Although mind-boggling advances in genetics, microscopy, computer science, photography, and toxicology will continue to expand the capability and effectiveness of the well-trained investigator, the principle role of the detective hasn't changed much since the days of Arthur Conan Doyle's great detective.
Nothing impresses a jury more than physical evidence that incriminates the defendant. But physical evidence has to be recognized, protected, properly recorded, collected, and interpreted. Moreover, physical clues are meaningless unless they are placed into the context of the case by a criminal investigator. All the science and technology in the world can't save a crime scene that has been improperly processed and investigated. In other words, physical evidence and cutting edge forensic science are only as good as the investigators working the crime.
As a general rule, a detective must solve the case identify the suspect before the forensic scientist can help prove the defendant's guilt through physical evidence. The modern detective, therefore, in addition to knowing how to deal with latent fingerprints, crime scene blood stains, shoe impressions, questioned documents, possible murder weapons, and all forms of trace evidence, has to develop and follow basic investigative leads, interview witnesses, utilize confidential informants, conduct searches, and interrogate suspects. To make matters more difficult, all of this work must be conducted within the hair-splitting and rapidly changing rules of criminal procedure. A missed Miranda warning or flawed search warrant and the evidence is out the window. The recent advances in science and technology have not made the job of solving crime much easier than it was in the days of Sherlock Holmes.
Slightly more than a hundred years ago Arthur Conan Doyle wrote that a first-class investigator had to have a good mind, exact knowledge, and the powers of observation and deduction. He might also have added persistence, audacity, objectivity, and integrity. Today, master detectives don't have to run fast, jump high, or shoot straight, because the act of criminal investigation involves the mind. It is a thinking person's game. In an era when pyramid power, poltergeists, flying saucers, psychics, and Elvis sightings are taken seriously by millions, the gifts of healthy skepticism and the ability to think straight are at a premium.
Although modern law enforcement leaders like to portray detectives as scientific investigators, the business of crime solving remains more art than science. It is a battle of wits between the investigator and the criminal, and in this war the best weapon is still a good mind.