Behind the Scenes of a Criminal Case: Learn How Fingerprint Evidence is Used
You have likely seen fingerprint evidence used on TV shows and movies but you may not have much experience with how it can be used in real life. In some cases, it can be used to help the defendant, in other instances it helps the prosecution. Today we will give you the basics of this evidence type. If you have questions, do not hesitate to contact The Mattern Law Firm at 310-342-8254 for a free legal consultation with an experienced attorney.
The Quality of Fingerprint Evidence
It may be true that fingerprinting does not seem as exciting as DNA typing but it is used very often. The idea is that there are no two people with identical fingerprints but this cannot actually be validated by science. However, it is considered extremely unlikely that two people would have exact fingerprints and as a result this evidence is considered to be reliable.
The Process of Matching Fingerprint Evidence
Matching fingerprint evidence involves following two basic principles. First, that the friction ridge patterns (i.e. the swirled skin on your fingertips) does not change over your lifetime, and second that no one else has these same friction ridges. It has been found that even identical twins do not share fingerprints.
A police officer may use fingerprints at a crime scene to compare to fingerprints they or the FBI has on file. There are many reasons a person may have their fingerprints on file, from prior convictions for criminal offenses or when they take on a certain occupation.
The Reliability of Fingerprints is Far from Agreed On
While most scientists believe that you can reasonably use fingerprints as evidence, there is not a clear consensus on how many points in common there must be to declare a match between two fingerprints. Some claim that a match based on just a dozen points in common is enough, while others say they need at least 20 points in common before they will agree to a match.
You may wonder: How are fingerprints found? The friction ridges described above have rows of sweat pores, and sweat mixes with other oils and dirt the body products or collects. That is then left on smooth surfaces. The fingerprint expert can use a powder and chemicals to make the fingerprints visible, though how visible the will be depends on a variety of factors.
One thing to note is that it is essentially impossible to prove how old a fingerprint is. As a result, it is often the case that an experienced defense attorney can easily explain away fingerprint evidence by noting that the defendant was at the place in question but it had been many weeks, months, or even years. Call The Mattern Law Firm at 310-342-8254 now for a free legal consultation.