Latent fingerprints are nearly invisble to the naked eye. They’re left when someone touches an object, leaving behind sweat and oils. Detectives make the print images visible by using powder that clings to the oily ridges of the fingerprint.

All police officers are trained to use basic fingerprinting equipment – brushes, powders, tape, and lifters.

 

Basic fingerprinting kit. 

Investigators use brushes to apply print powder. The best brushes are made from the feathers of a maribou, a member of the stork family. A second type brush – camel hair – is also an excellent brush. Interestingly, camel hair brushes are not made from the hair of actual camels. Instead they’re made from the hair of small mammels, such as rabbits and squirrels. Synthetic brushes are widely used because they’re less expensive than the other types.

Maribou feather brush

After a print has been developed, the detective uses tape that’s similar to wide packing tape to lift the print from the surface. She then presses the tape and captured fingerprint against a white card creating a permanent piece of evidence.

Another great tool – my personal favorite –  for lifting prints is a hinged fingerprint lifter. The front of the lifter is a small square of tape. The second part of the lifter is a white backing. The print is lifted with the tape which is then pressed tightly against the backing to preserve the fingerprint. Lifters come with pre-printed spaces for the date, time, officers initials, and case numbers.

Hinged fingerprint lifter.

* All photographs courtesy of my friends at Sirchie Finger Print Laboratory

* Notice – The Graveyard Shift is pleased to announce a special guest blogger on Monday 3-3-08. Sgt. John Howsden (ret.), a thirty year veteran police officer, will be discussing body armor (Kevlar vests). Stop by and pick his brain. As usual, we’ll have some cool photographs. One is really cool.

* Fingerprinting will continue next week. Be prepared to take lots of notes.

 

 

 

 

Uniformed officers are normally the first police officers on the scene. It’s up to these front-line cops to take charge, calm the chaos, and make things safe for the arriving investigators. Sometimes, crime scenes are large and complicated; therefore, it may be necessary to set up a command post – a central location for coordinating police activities.

Many police departments use mobile command centers, such as converted motor homes and travel trailers. Some patrol supervisors drive vehicles designed to quickly transform into a fully functional command post.

This Oregon police sergeant drives a marked SUV that also serves as a command post during emergencies and crime scene investigations.

Crime Scene Investigation facts:

Patrol officers often assist police investigators with the recovery and collection of evidence.

Not all crime scene investigators are sworn police officers. Many police departments employ specially trained civilian crime scene investigators/technicians. These crime scene investigators do not:

(As seen on TV)

arrest criminals

interrogate or question suspects

carry weapons

participate in, or conduct autopsies

drive Hummers

All police officers are trained to properly collect and preserve evidence. Sometimes, detectives are unavailable; therefore, uniformed officers assume the duty of investigating the crime.

 

Ohio police sergeant assists a detective with the collection of a firearm.

Crime scenes may be as small as a single room and they can be as large as the site of the entire area encompassing the collapsed World Trade Center towers.

The police are in charge of crime scenes. Coroners and medical examiners are in charge of the bodies of murder victims.

Next – Crime Scene Evidence

 

 

Most crime-scene investigations begin with a 911 call to police. A communcations officer, or dispatcher, receives the call and obtains as much information about the crime as possible, such as the caller’s name and address, weapons involved, number of victims, and the suspect’s name and description.

The dispatcher relays the information to the next available uniformed patrol officer. Patrol officers are normally the first officers to arrive on the scene of a crime.

The first officer who arrives is normally in charge of a crime scene until she is relieved of that duty by a superior officer or a detective.

Patrol officers must quickly assess a scene and determine if they should call for additional back-up, EMS, detectives, supervisors, medical examiner, crime scene technicians, and other necessary personnel. They also give emergency first aid, if needed.

Patrol officer responds to emergency call.

When a patrol officer approaches a crime scene, he does so with caution. He must be certain there are no hidden dangers, such as a concealed suspect, no dangerous gases or chemicals, downed power lines,  and booby traps. Booby traps are quite common with houses and areas occupied by drug dealers.

Once officers determine that all is safe and that a crime has indeed occurred, they call for investigators. Patrol officers must secure the crime scene and protect evidence by keeping everyone outside until investigators arrive. Patrol officers are also responsible for obtaining the initial information – name, address, phone numbers – from witnesses.

A crime scene is secured until investigators arrive.

Detectives normally take charge of all major investigations.

Tomorrow – Crime Scene Investigation – Part 2.