Last week as I watched jury selection, many of the jurors claimed they had been burgled and the cops hadn’t done anything to catch the criminal. Therefore, the prospective jurors suggested, they might be biased against police witnesses. This was either an effort to avoid jury duty, most likely, or an ignorance of standard police operations in our country.
Regardless of these jurors, there is a vast ignorance of police work, fed aggressively by police, law and crime shows on TV and in movies. The most phantasmagoric TV show is CSI, a show that suggests actual scientific work is used in crime fighting.
I wish to suggest two realities of police work. One is what does work in criminal investigation and two is what doesn't work.
One thing and one thing alone works: answering the phone so the police can get the tips and eyewitness information that allows them to do their work. This is a fact of life at all levels of investigative work --- the FBI, Workers-Comp and the CIA.
Several things are done to generate tips that make police work possible. Talking to people in the area where the crime occurred helps because that way relevant citizens know who at the police department to contact and citizens get some sense of trust for the people they deal with.
It sometimes helps to post rewards for tips and to hire informants to regularly report on information they gather in their everyday association with outlaw society.
Science is just not part of investigation. Fingerprints, DNA, blood, semen and anything else that is collected has one purpose. It is not used to search for the perpetrator. Evidence is to use for building a case when a clear suspect is found.
Before 1980 there was no central fingerprint file. Local police, like the officers I knew in San Francisco had ten thousand local finger prints but no way to search the files, except by the name of the finger printee. The same remains true today. There are only limited central files of DNA that are searchable and they only include a small sample of the population. That small sample is better than nothing since includes people who have usually had some contact with the law.
Police collect evidence, wait for the phone calls of interested parties to finger the potential perpetrator (s), and then investigate the accused to see if the evidence and alibis fit. It there is more than one perpetrator, the police will try to get one to testify against another in return for a lighter sentence. This applies to spies as well as burglars.
That is police work. That is the long and short of it. That is also the way the FBI and nearly all other investigators work.
So, back to the jurors disappointment at the police. Police often don’t waste time collecting prints at burglary sites, because burglars are rarely caught except when they are caught in the act. And, burglars are rarely caught unless they sell stolen goods to an undercover fence.