In the past few decades, DNA technologies have taken off. Thanks to these advances, DNA plays a much more important role in criminal cases than it did in the past. Forensic scientists are able to extract and analyze DNA from crime scenes to help police identify suspects to a crime and to help the government prove its case against a defendant.
Even though DNA technology has become more reliable, it is still not perfect. Courts are often thinking and rethinking the role DNA evidence should play in criminal cases.
How is DNA used to solve crimes?
There are two different ways DNA is typically used to solve crimes.
The first occurs when police have identified a suspect. In this case, a sample of that person’s DNA will be compared to evidence from the crime scene. Doing this helps law enforcement determine if the suspect committed the crime.
The second occurs when police have not identified a suspect. In this scenario, forensic scientists will typically collect biological evidence from the crime scene. They then analyze this evidence and compare it to offender profiles in DNA databases. Matching information may lead law enforcement to identify a suspect.
What are DNA databases?
The government uses DNA databases to link DNA samples collected from a crime scene to people who have been convicted of crimes in the past. These exist on both the state and the federal level and help law enforcement when police have not identified a suspect.
For example, if a person is the victim of a sexual assault, a Sexual Assault Nurse Examiner (SANE nurse) will often collect an evidence kit from that person. Forensic scientists then develop a DNA profile of the suspected perpetrator using swabs in the kit. This profile is then searched against state databases of people convicted of crimes with profiles in the database. If the laboratory determines there is a match, they forward the information of the matching person to law enforcement.
In the late 1980’s the federal government passed a law establishing a Combined DNA Index System (CODIS). CODIS is run by the FBI, and its purpose is to encourage cooperation between federal, state, and local governments in keeping DNA databases. State DNA databases are structured based on CODIS.
Does Massachusetts have a DNA database?
Massachusetts participates in CODIS and has its own DNA database run by the state police. Under Massachusetts General Laws Chapter 22E, Section 3, any person in the state who is convicted of a crime punishable by state prison time must submit a DNA sample.
A convicted person’s DNA sample is confidential, but it can be accessed by:
- State and local police departments
- Forensic analysts working for the police
- Federal law enforcement agencies
- A convicted person who submitted a sample to the database and has been identified and charged with another crime as a result of a search of the DNA database (limited only to that person’s profile)
If my DNA is in the database, is there any way to get it out?
You can expunge your DNA profile from the state police database if your conviction was reversed and the case was dismissed. However, this conviction must be the same conviction that resulted in you having to submit the DNA sample to begin with.
What are some issues with using DNA evidence in court?
Scientists and experts in the legal community have often criticized the reliability of DNA evidence. Here is a list of some common issues they have pointed out:
- Forensic scientists may collect DNA at the crime scene that was already there before the crime was committed. This could lead to a false connection between an innocent person and the actual perpetrator of a crime.
- DNA evidence may also be deposited at the scene of the crime after the crime was committed, by an innocent person, but before police could secure the area.
- DNA collection technology is very sensitive. This is both a good and bad thing. It’s good because it makes it easier for forensic scientists to collect DNA samples. It’s bad because it makes it easier to contaminate the collected DNA.
- People shed DNA at different rates. DNA is found in bodily fluids but also comes from pieces of the skin and hair. Skin cells and hair often detach from a person without them knowing, but for some people it detaches more frequently than others. This also poses a risk of a mismatch.
While DNA is a powerful tool to help law enforcement identify people who have committed crimes, mistakes often happen. In many instances, DNA identifications can be decisive in a criminal case. For these reasons, if you are charged with a crime involving DNA evidence, it is important to hire a lawyer who understands the ways DNA evidence may be unreliable or invalid.
IF YOU OR A LOVED ONE HAVE BEEN ACCUSED OF A CRIME BASED ON DNA EVIDENCE, AND YOU NEED AN EXPERIENCED CRIMINAL DEFENSE LAWYER WORKING ON YOUR SIDE TO PROTECT YOUR RIGHTS, PLEASE CONTACT CRIMINAL DEFENSE ATTORNEY WILLIAM J. BARABINO.
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