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  • Writer's picturePat Pegan

Solving a Sexual Assault Case with Forensic Genetic Genealogy:

A Closer Look at the DNA Technology that Helped to Capture an Unidentified Rapist in Acton, Massachusetts

Nine years ago there was sexual assault that happened at the commuter rail station in Acton, Massachusetts. Now, 28-year-old Lunenburg resident Christopher Aldrich has been arrested and charged with Aggravated Rape. Acton Police Chief James Cogan and Massachusetts Middlesex District Attorney Marian Ryan made the announcement about the breakthrough in the case on Tuesday, February 21, 2023, after utilizing forensic genetic genealogy data in order to track him down. Aldrich was charged in Concord District Court, and after a hearing, the Judge ruled that he should remain in custody without bail pending a dangerousness hearing.

Forensic genetic genealogy is revolutionizing the way law enforcement solves crimes. By utilizing publicly accessible DNA data collected by companies such as and others, investigators are able to identify suspects with unprecedented accuracy. This new investigative technique has far-reaching implications for people who choose to share their personal DNA profiles with these companies, as well as criminal defendants who must now grapple with a powerful tool that can be used against them in court.

Addityionally, I will discuss some of the strengths and weaknesses in DNA evidence, the ethical implications, as well as my role as a defense attorney both inside and out of the courtroom.


DNA Helix

In 2013, a white man with a knife sexually assaulted a 22-year-old woman at an Acton Massachusetts commuter rail station. Despite arriving at the scene within minutes of the victim's call to 911, the police were unable to identify the attacker due to the lack of security cameras in the area. The victim received medical care at a local hospital, and the State Police Crime Laboratory's chemists were able to generate a comprehensive DNA profile of the perpetrator from forensic data collected during the investigation. However, attempts to match the profile to national and state criminal databases were unsuccessful.

Despite thorough investigations by the Acton Police Department and Transit Police, the perpetrator was not found until 2021, when Christopher Aldrich was named as a person of interest as a result of a forensic genetic genealogy examination by Parabon NanoLabs, which searches public genetic genealogy databases to create family trees.

On November 9, 2022, Mr. Aldrich crashed his Ford Crown Victoria into a utility pole on School Street in Acton. The officers of the Acton Police Department who responded to the scene obtained several items from Aldrich's car and swabbed them for DNA. Staff members at the crime laboratory were able to create a significant male DNA profile from each item, and both profiles matched the perpetrator's DNA profile obtained from the 2013 sexual assault investigation. Subsequently, Aldrich was arrested and charged with aggravated rape.

What is Forensic Genetic Genealogy?

Over the past ten years, the use of direct-to-consumer DNA testing has skyrocketed. it is believed that 100 million people worldwide have shared their genetic data with companies like AncestryDNA, 23andMe, and FamilyTreeDNA. Law enforcement agencies have benefited from all that DNA because they've learned that "investigative genetic genealogy" is much more successful if searches aren't limited to DNA found at crime scenes.

Technology has revolutionized the way investigators are able to identify suspects in criminal cases. One of the most powerful tools they have is a technique known as genetic genealogy. This cutting-edge method involves entering a DNA profile into public genealogical databases in order to build a family tree that can lead them closer to an unknown suspect. By using this tool, investigators can track down suspects who left their DNA at crime scenes in recent years – something that was once impossible before the advent of genetic genealogy.

How are Public Genealogical Databases Built?

Public DNA databases are created by companies like and 23andMe which compile and store voluntarily submitted DNA profiles of their customers in order to create family trees that can help users trace their ancestry. In addition to this, these companies also store DNA profiles from other relatives of their customers, such as third and fourth cousins. This means that if a relative of someone in the database is identified as a suspect in a criminal case, law enforcement can use the DNA profile to track them down by identifying the family tree and searching for potential matches.

How can Law Enforcement Access this Information?

Law enforcement agencies can access public genealogical databases in a number of ways. The most common is through the use of a search warrant or subpoena, which requires companies to provide information that may aid in an investigation. In addition to this, some companies have created their own partnerships with law enforcement and allow them direct access to their databases outside of legal channels. This means that police can run their own searches for potential suspects and use the data to build a family tree, which can lead them closer to a suspect in a criminal case.

Strengths and Weaknesses of DNA Evidence

DNA evidence has revolutionized the judicial system, allowing for more accurate and reliable determinations of responsibility for crimes. DNA analysis is an extremely scientific method which relies on DNA patterns to assign probability to a certain individual or group’s involvement in a crime. DNA evidence is incredibly powerful in determining guilt or innocence and is sometimes accepted as the sole factor of evidence necessary to arrive at verdicts. This reliance on DNA evidence has its merits as it eliminates doubts of criminal identification, but it also has its weaknesses as DNA can be easily compromised due to insufficient chain-of-custody protocols and laboratory methods. In order to ensure DNA evidence is truly reliable, tedious guidelines must be followed throughout the entire process of collection and analysis.

Ethical Implications of Using DNA Evidence

DNA evidence is becoming more commonplace in criminal proceedings and investigations, bringing up questions about the ethical implications for its use. DNA repositories, public ancestry sites such as 23andMe, and DNA tests of individuals seeking medical advise from third party companies all pose potential risks to personal autonomy. When DNA becomes publicly accessible, it can be used to identify people from distant relatives, or track down innocent individuals who may have DNA similar to a suspect’s. Family Tree DNA and GEDmatch enable law enforcement to use, or ask users to consent to having their profiles accessed by the authorities.

There is also the danger of misuse by law enforcement in DNA testing of a person without proper authorization or consent given. As DNA technology continues to become increasingly ubiquitous, serious consideration must be given to its use and how it can be safely and ethically managed.

What Needs to be Done to Ensure that DNA is used Ethically in Criminal Proceedings?

DNA evidence has become an increasingly important factor in criminal proceedings, allowing for greater accuracy and reliability when determining guilt or innocence. However, its use must be carefully managed to ensure it is used ethically and responsibly. 4th Amendment protections must be respected by law enforcement personnel when collecting DNA samples from suspects without their consent or with proper authorization. Defense attorneys also have a responsibility to ensure that any DNA evidence presented against their clients was collected ethically and lawfully. Finally, the public should be made aware of the potential risks associated with using publicly accessible sites such as 23andMe and GEDmatch which can lead to individuals being identified from distant relatives or tracked down based on similar DNA profiles. By taking these steps we can help create a more just society by ensuring that DNA evidence is used ethically in criminal proceedings.

The Defense Attorney's Role

As DNA evidence has revolutionized the criminal justice system, so too has the role of the defense attorney become more important than ever. A good defense attorney is a careful investigator, verifying facts and any corresponding police procedures thoroughly. Defense attorneys are essential to ensuring that their clients receive fair trials, which means it is essential that they have a thorough understanding not only of DNA evidence and the law, but also of police investigation techniques as they relate to DNA results. Defense attorneys have become crucial in upholding justice with DNA in criminal cases, using every bit of knowledge in their arsenal to protect their clients rights and ensure that they get a fair trial.

If you or someone you know has been questioned by police or charged with a crime in Massachusetts, it is important to consult with an experienced Massachusetts criminal defense attorney. At Regan Law, we have decades of experience dealing with cases which involve DNA evidence. Our team is well-versed in 4th Amendment protections and we fight to ensure that our clients receive a fair trial. Call us today at (978) 74-1220 or fill out the form on our contact page for a free consultation and case evaluation. No matter how complex your case may be, my team and I can provide the legal representation and support you deserve.

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