Have you ever heard a CSI refer to a latent lift card? Chances are you have…but have you ever seen one? When CSIs develop a powdered fingerprint they have to lift it with tape. Then they affix the tape to a card which then allows the examiner to compare it without damaging it (since the powdered impression is protected by the tape). Some people think that the cards just contain fingerprints but that’s not true. Do you know what kind of information is (or should be) contained on it? A proper fingerprint lift card has two sides. Most cards are white colored about 3″ x 5″ card stock type paper. Black colored cards (glossy side) are also available for using light colored powders. Larger cards do exist for full hand or palm impressions as well but these are less commonly used. Generally the fingerprint side has a glossy finish. The other side of the card contains important information for the analyst and the courts. You see, it’s not enough to simply have a suspect fingerprint. You need to have additional value to give it any (legal) weight in court.
One important piece of information contained on the fingerprint side is what we refer to as an orientation arrow. This allows the examiner to orient the print on the object or surface it was lifted from. This helps the examiner determine how the object was touched. Common orientations include “up” (doors/windows), “front” (vehicles), “north” (horizontal plane), or some feature of the object like “towards muzzle” (firearms).
The back side of the card contains a lot of important case information like the case report number. This is the unique number that identifies a specific call/location/crime. There are a lot of different formats but most contain a year and sequential number of the call (i.e. 2012-1234 or the 1,234 call to police in the year 2012). The location (address) of the call is also listed. Some crimes involve multiple locations. In a bank robbery you might have evidence recovered from the bank, getaway vehicle, and suspect’s residence for example. These areas may be processed over a couple of days as well so the date and time of collection/development is also important. Was this the print developed on March 20th or April 3rd?. The examiner’s name and badge number are also important for the chain of custody. A CSI may also make a small sketch (say of a car door window) and indicate exactly where the print was lifted. Simply saying it was collected from a window may not give an accurate picture. Was it from the top of the window or bottom? Was it on the inside (private) of the door or outside (public). All of this information is important to better evaluate the probative value of the print. A fingerprint on the outside of a victim’s vehicle may not be as suspicious as one found on the inside.
Now sometimes officers get distracted or busy and they forget to mark some or all of this information. This can cause a lot of uncertainty when evaluating the value of the evidence. Here is where it can get interesting for you as a writer. You can use this lack of information to create some uncertainty in your story. Imagine your CSI checks out evidence from a crime and finds a suspect fingerprint. But the card doesn’t say where the card was collected or who even collected it! You can’t even be sure it is associated with the crime in question because there is no case number on it. Isn’t it possible the officer mistakenly mixed it up with the cards from another case at the end of shift when they booked it into evidence? After all, how would they know right? Now this rarely happens and when it does it’s usually on a minor crime. But what if it was a homicide? You know Mr. X’s fingerprint was found, but where? Consider using that seemingly minor mistake to build a lot of tension and uncertainty in your plot.