Collecting fingerprints is part and parcel of almost all crime scene investigations in the world. Below are some of the techniques used to obtain these prints.
Latent Prints and Known Prints
Latent print refers to the fingerprints that are left behind (i.e., in a crime scene). Latent print refers to prints that are left accidentally. Those that are willingly submitted are called known prints.
Known prints are usually taken by way of black ink. After putting the thumb in the ink it is pressed onto a white card. This process is used when traveling, processing documents and others.
Lifting Latent Fingerprints
There are many methods crime scene operatives rely on for collecting fingerprints. The most commonly used technique is dusting. A brush and special dark powder is used.
When the crime scene investigators arrive, the latent print technician starts looking for fingerprints using the powder and brush. A sticky tape is used to lift the fingerprints. The prints are stored in an evidence card.
A latent print examiner will analyze the prints in the lab. They’ll attempt to match it with another one in the FBI’s IAFIS (Integrated Automated Fingerprint Identification System).
The dusting agent works because it sticks to the oil in the print. The sticky tape is used to lift the oil and dust.
Note: dusting isn’t always an effective method for collecting fingerprints. If the material has been touched, the findings could be compromised and the results inconclusive.
Another method is by using an electric pen and a metal filing brush. This brush is actually an electromagnet that takes up iron fillings. Unlike ordinary brushes, this doesn’t affect the prints. What happens is that the prints stick to the oils. This is also lifted using sticky tape or other adhesives.
Chemical Bonding Agents
Authorities also make use of special chemical bonding agents. The oily object is set in a specially heated area. Superglue fumes are used to warm the environment. This will create a white substance on the print. This method has been used for collecting fingerprints for several years now.
Gray Scale and Other Technologies
The gray scale is used by a lot of police operatives. The gray scale utilizes 256 shades of gray (from black to white). The systems used to take the prints vary, but livescan technology is becoming the norm.
Livescan uses a variety of laser technology to assess fingerprints. A glass pad is used to obtain clear prints. The results are relayed to the database to look for any other matches.
In addition, police officers now use fingerprint cards and images to verify matches. Cameras are also used to collect various prints.
Biometric handheld gadgets are also available for taking fingerprints on the spot. These devices are linked to the main database system. When prints are taken, these can be matched and searched for in the database. This can be done without taking the suspect to the police station.
With rapid advances in technology, the ways of collecting fingerprints will increase and become more sophisticated. This will provide tremendous benefits to society in general.