How Police Solve Whodunits

Mystery writers, as well as other genres, have always asked me at book conferences how police investigate crimes. Do they approach a sex crime differently than a murder? What about a kidnapping versus a bank robbery?

The truth is yes, they are investigated with some subtle nuances, but the overall basic Police Investigation 101 is a common thread in all police investigations.

Unless the police have a “smoking gun,” that is to say, when called to a murder scene of a person being shot, and arrive to see the accused leaning over the corpse, warm gun in hand, who admits, “I killed him,” then they have a “whodunit.”

Some cases lend themselves to more forensic evidence than others.

Sex crimes oftentimes, but not always, have bodily secretions, hairs, fibers, wounds, bite marks, etc.

A bank robbery may have none of these, other than a grainy black and white surveillance tape. The suspect wore a mask and gloves, and acted quickly. He threatened the teller verbally, slightly displaying a firearm. There was no physical confrontation, or struggle as in a sexual assault. Perhaps his accent or manner of walking was unique, but if properly covered up, his tattoos aren’t visible, and he left his piercings home.

The investigation process is a process of elimination. As Sherlock Holmes once said, “When you have eliminated the impossible, whatever remains, however improbable, must be the truth.”

A person is murdered.

Until some good forensic evidence develops, the police need to have these questions about the victim answered:

Who would want them dead?

Who would gain from their death?

Who would profit from their death?

Who would have a reason to kill them?

Randomness in murders does occur, but is not nearly as often as portrayed on the television shows.

Most victims always, in some way, either know their killer, have met their killer, have seen the killer before, or are known to the killer.  

That’s why at a murder scene, the VICTIM is THE most important piece of evidence. Forgetting about the physical evidence that could be found on the victim’s body for a second.

The victim had friends.

The victim had enemies.

Some cases are true “whodunits.”

As this is being written, a Malaysian aircraft, Flight MH-370 that had departed from Kuala Lumpur, is missing with hundreds of passengers aboard. No remnants of the plane have yet been found. No debris. No bodies. No oil slick. No communication from the pilots regarding a distress signal. No distress beacon found flashing. Nothing. Zero.

How can a Boeing 777 with hundreds of passengers just disappear with no evidence to be found?

Let’s look at the forensic evidence. What has been found.

Nothing.

Bodies float. Debris from airplanes float. Food trays. Newspapers. Clothing. Luggage. They all float.

The only forensic evidence of value reported so far is an oil slick, of which samples have been taken to see if it matches fuel from the aircraft. Other than that, there is no forensic evidence.

Or is there?

Sometimes, the LACK of forensic evidence found speaks volumes about what actually happened.

So, let’s look at the non-forensic evidence.

In this airplane case, it has been determined that two stolen passports, one from an Austrian and one from an Italian have been used to purchase tickets for this flight. These passports were stolen years ago in Thailand.

Now these passports were suddenly used to purchase airline tickets. And the tickets were issued consecutively, one right after the other. By the same ticket agency. Paid for in cash.

Coincidental, my dear Watson?

Stolen passports are evidently used quite often overseas. But, used on the same flight? A flight that suddenly goes missing? And the tickets purchased consecutively?

The most common theory reported now is “catastrophic breakup.” And even though there is a small army of planes and aircraft attempting to find it, it is difficult because the plane’s exact location at disappearance is unknown, and the search area is hundreds of miles. But, what if no debris is ever found?

One strong possibility not mentioned is hijacking, which would account for the lack of debris. But then, why would no contact be heard from any of the hundreds of passengers either calling or texting or e-mailing relatives? Perhaps the plane was out of range for such transmissions. Perhaps not, and the passengers are in fear to do so.

I can only hope all are safe, and will be found safe.

This is a true whodunit, one that will need to be solved by a process of elimination. There is no smoking gun.

Remember in your writing the important process of elimination used by the police in solving crimes.

More importantly, in your prayers remember these passengers and crew.

“When you have eliminated the impossible, whatever remains, however improbable, must be the truth.”