Archive for February, 2008
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.
Detectives use a variety of means to collect crime scene evidence. When attempting to locate evidence, investigators must be methodical. One way to be certain they’ve combed every inch of a crime scene is to conduct structured, patterned searches, such as spiral or grid searches.
Spiral search patterns are an effective means of locating evidence.
Grid search patterns are especially effective when searching large areas, such as a field or other open land areas. Each grid block is assigned a number or letter. Detectives use those identifiers as reference points when testifying in court. Example: “I located the murder weapon in block number 4. I also discovered spent bullet casings in block number 3.”
Alternate light sources (ALS) are useful when attempting to locate hard-to-see evidence, such as fingerprints and body fluids. Devices such as Sirchie Fingerprint Laboratory’s Krime Site Imager are invaluable for detecting and capturing fingerprint images. The KS Imager is battery operated and is capable of recording images in bright light or in total darkness.
All too often, fingerprints are destroyed during crime-scene processing (dusting and lifting prints) Using a device such as the KS Imager allows investigators the opportunity to photograph a perfect image of a fingerprint before attempting dust and lift it. Therefore, even if the print is marred, detectives will still have perfect image of the print, an image that’s permissible as evidence.
A detective uses a Krime Site Imager to locate and photograph fingerprint evidence.
Some crime scenes, such as labs used for manufacturing methamphetamine, contain hazardous materials, such as flammable and toxic chemicals and fumes. When searching those dangerous crime scenes, investigators must wear protective gear and clothing.
A detective wearing a hazmat suit gathers evidence from a meth lab.
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)
interrogate or question suspects
participate in, or conduct autopsies
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
Okay, our alert patrol officers have determined that they do indeed have a crime scene, and they’ve called in the detectives—us. Before we get started with our investigation, let’s be sure we’re all on the same page.
Everyone knows the difference between a murder and a homicide, right? How about the difference between a crime scene and the scene of the crime? You knew they weren’t the same, right?
First of all, let’s talk about homicide. Homicide is the killing of one person by another. A homicide can be ruled legal if the act was committed in self defense or in the defense of another. Even state executions are homicides.
Homicide is the act of one person killing another.
Murder is a homicide, but…
The scene of a crime is the actual location where a crime was committed—where the killer pulled the trigger, or the spot from where the car was stolen.
A crime scene is any location where evidence of a crime can be found. For example, a suspect robs a bank at gunpoint. The bank is the scene of the crime because that’s where the crime took place. It’s also a crime scene because evidence—fingerprints, video evidence, etc.—can be recovered there.
Scene of the crime. The place where the crime took place.
The robber drives three blocks away and tosses his mask and gun into a dumpster. The dumpster and surrounding area are now a crime scene because evidence of the robbery can be recovered from the area.
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.
Fire up the Land Rover, grab your pith helmet, and practice your best Tarzan yells because this week’s Weekend Road Trip takes us to beautiful South Africa.
Mystery/romance author Terry Odell was kind enough to lead the way through the dark jungles by providing some great photos. Remember, keep your hands and feet inside the car at all times!
You can visit Terry’s website at http://www.terryodell.com/
Hiking to the lighthouse on Cape Point.
Kruger National Park game drive.
Valley of Desolation.