How to Lift a Fingerprint: For the Beat Cop

Fingerprints are a valuable tool for law enforcement in solving crimes. Many crimes are solved with a single fingerprint. For that reason it is very important for law enforcement officers to know the basics of lifting a latent print. In this article I will explain the basics and essential tools needed to lift a fingerprint and hopefully help you solve that crime.

With all the crime-dramas on TV like the CSI series of shows, the general public believes that most police departments have all this high-tech equipment that will get their stolen TV back, so they won't miss the latest episode of CSI. Unless you work for LAPD, NYPD, Dallas PD or some other department with a budget that exceeds many small countries, then you probably only have the basic equipment to lift prints and you definitely don't have a crime scene technician available.

WHAT YOU NEED:

What you need are just some simple tools that are readily available and inexpensive. Every patrolman should have a crime scene kit. In this kit you should have a fingerprint brush, fingerprint powder, lift tape, lift card, digital camera, flashlight and a knife. You don't need to go out and buy the best of each of these items. If your department will not provide this equipment to you, you can purchase this equipment online at websites such as PoliceOne.com or you can get it through many law enforcement magazines such as Galls. Your fingerprint brush can be which ever kind you become most comfortable with. There are fiberglass brushes available as well as magnetic brushes. I have found it is best to have both. Many times the type of surface you lift the print from will determine which type of brush to use. You should have at least two types of powder. Basic black powder is essential. This will be your most used powder. I also recommend a light colored powder such white or silver. You will need this for lifting a latent print from dark surfaces for contrast. For the latent print card I recommend using 3" x 5" card. Many are pre-made with case information on them. You can also go Wal Mart and buy a pack of index cards. They will work just as well. Just because you try to be economical does not mean your going to lose that case. The digital camera is not a requirement, but it is useful for documenting the scene. Any knife will do, just make sure you keep it sharpened. Any flashlight will do as well.

HOW TO LIFT A LATENT PRINT:

When you go to a scene, usually this will be a burglary or breaking or entering, you will first get the story from the victim. At this point it is important to ask the right questions. You will need to not only know what was stolen, but what may have been touched. Items that have been touched are where you will solve your crime. Every person leaves a latent print when they touch a surface. There are exceptions, but for our purposes we will assume that our criminal does not suffer from a medical condition that prevents this. A latent print is actually the oils and residues that are deposited from our skin. When we lift a latent print, we are lifting the deposits. The first thing you want to do is find the latent print. Look at the surfaces that your criminal may have touched. Smooth surfaces are the best, such as glass or metal. Porous surfaces are more difficult to retrieve a latent print from and often require a different technique, i.e. superglue fuming or iodine. We are not going to discuss those. To lift your discovered latent print, pick your brush and your powder. As I said before, the brush choice is up to you. Now choose your powder. Black powder is the most commonly used. You will need the light colored powder for a contrast if you surface is dark. Don't fill your brush with powder. A common mistake is that many officers will use too much powder and this will damage and usually overdevelop the print. I like to shake up my powder jar and then remove the lid and then place the brush in the lid. There is normally enough powder in the lid to get the job done. Next, lightly twirl the brush over the jar to remove excess powder. Now is the time to develop the latent print. I use the twirl technique. You twirl the brush lightly over the latent print for a short time until you see the print. Once you have a visible print, stop using the powder. Now is the time to get your lift tape. Unroll a short strip of tape, approximately six inches long, don't cut it yet. I like to fold the end back on itself. This will give you a non-stick surface to hold onto. Place the tape just above the latent print and press it down until a small section holds while you keep the remainder of your exposed tape away from the latent print surface. Slowly slide the tape down on the surface until it completely covers the latent print and the area on either side. I recommend using some sort of straight edged object to slide the tape on with. A credit card or you police ID will do. Now take the knife and cut the strip of tape from the roll. Get your latent print card. Now is where the folded back part of the tape comes in handy. This gives you a handle to pull the strip of tape up with. Lift the tape off of the surface and place it on you latent print card attaching it from one end of the card to the other. Never start from the middle and work out. Make sure your lifted latent print is securely attached to the card. You can use your straight edge again to do this and it will also help remove any possible air bubbles that may have popped up. Always label your latent print with the location the print was lifted from, date, time and case number. Initial the card and if possible you can draw a diagram showing where the latent print was lifted.

Additional note, the flashlight comes in handy at night or any time you do not have a constant light source available when you're looking for those prints.

Good luck and let's be safe out there.