Law Enforcement Departments Solve Cold Cases Using New DNA Technology

DNA Technology

Every law enforcement department around the nation has unsolved cases that could be solved through recent DNA technology advancements. Today, researchers who understand that evidence may yield a DNA profile may identify a suspect in a sense previously seen only on television. Evidence invisible to the naked eye may be the trick to solving a sexual assault, residential burglary, or murder.

The saliva on the stamp of a stalker threatening letter, the sweat on a rapist’s mask, or the skin cells slough on the ligature of a strangled kid may hold the key to solving a crime.

However, DNA is not the only forensic tool available for the analysis of unsolved cases. Improvements in DNA testing and the benefit of DNA database systems have prompted law enforcement agencies across the nation to reevaluate cases earlier thought unsolvable.

Changes In The Law

Advancements in DNA technology have resulted in significant changes in several states’ statutes, which might impact the way unsolved cases are reviewed, recorded, and prosecuted. Progress in the technology is so significant that laws are being made, amended, and sometimes even repealed, to benefit from its capacity to identify and condemn the guilty and exonerate the innocent.

The laws on DNA admissibility in court, its use in post-conviction appeals, the development, and growth of databases, along with the expansion or elimination of statutes of limitation are examples of this fast-evolving effect of DNA on the criminal justice system. Given the legal changes happening throughout the nation, continuous contact and consultation with the local prosecutor are critical not just for the investigation of old cases but for many cases but for all cases in which DNA could be relevant evidence.

Innovations In DNA Technology

Innovations in DNA analysis and computer technology and the Combined DNA Index System (CODIS) have created a strong crime-fighting tool for law enforcement. CODIS is a computer network that joins forensic DNA labs at the state, local, and national levels. DNA database systems that use CODIS have two primary criminal indexes and a missing persons index. When a DNA profile is made from crime scene evidence and entered to the CODIS forensic (crime scene) index, the database software searches thousands of convicted offender DNA profiles (included in the offender indicator ) of people convicted of crimes like rape and murder.

Much like the AFIS (Automated Fingerprint Identification System), CODIS can help investigations by effectively matching a DNA profile made from biological evidence left at a crime scene against condemned offender DNA profiles and forensic evidence from other cases included in CODIS. CODIS also aid investigations by looking at the missing person index, which comprises DNA profiles of unidentified ones and DNA profiles of relatives of missing people.

What is CODIS?

CODIS is a computer software application that operates local, state, and federal databases of DNA profiles from condemned offenders, unsolved crime scene evidence, and missing persons. Every state in the country has a statutory provision for establishing a DNA database that enables collecting DNA profiles from criminals convicted of particular crimes.

CODIS software empowers state, local, and national regulation enforcement crime laboratories to compare DNA profiles electronically by linking serial crimes to each other and identifying suspects by matching DNA profiles from crime scenes with convicted offenders’ profiles. The achievement of CODIS is demonstrated by the thousands of matches that have linked serial instances to one another and cases that were solved by fitting crime scene evidence to known convicted offenders.

The missing person index consists of the unidentified person index and the reference index. The unidentified person’s index has DNA profiles from recovered remains, such as teeth, bone, or hair. The reference index comprises DNA profiles from related individuals of missing persons to be periodically compared to the unidentified person index. All samples for this index are typed using STR DNA and mtDNA analysis (if possible) to maximize the ability to advance technology.

Due to the recidivist character of violent offenders, a DNA database system’s power is evident, not just a sensitive PCR system reproduces any kind and all of the DNA contained in an evidence sample. Greater attention to contamination issues is necessary when identifying, collecting, and preserving DNA evidence. When properly recorded, organized, and saved, biological evidence can be examined to make a trusted DNA profile years, even decades after it’s collected.

Just as data collected from a crime that happened yesterday can be examined for DNA, now proof from a bloody shirt, old rape kit, or stained bedclothes may have a valuable DNA profile. In combination with an evolving database system, these new analysis methods make a strong argument for the reevaluation of unsolved crimes for possible DNA data.

Experienced law enforcement officers take advantage of strong DNA analysis techniques by investigating crime scenes with a keener eye toward biological signs. The same new method applied to crime scene processing and current case investigation can be applied to previously unsolved cases.

Throughout the country, law enforcement agencies establish cold-case squads to review old cases for DNA and other new leads. Below are the DNA analysis being done.

PCR Analysis

PCR (polymerase chain reaction) advances DNA analysis and has allowed labs to develop DNA profiles from extremely small biological evidence samples. The PCR technique reproduces exact copies of DNA in a biological proof sample without affecting the original, similar to a copy machine.

RFLP analysis needs a biological sample about the size of a quarter, but PCR may be used to replicate millions of copies of the DNA contained a couple of skin cells. As PCR analysis needs just a minute quantity of DNA, it can allow the lab to investigate highly degraded proof for DNA.

On the other hand, since the sensitive PCR technique reproduces any and all of the DNA found in an evidence sample, a greater focus on contamination problems is necessary when identifying, collecting, and preserving DNA evidence. These factors may be especially important in evaluating unsolved cases where evidence might have been inadequately collected or stored.

STR Analysis

Short tandem repeat (STR) technology is a forensic analysis that assesses specific areas (loci) located on nuclear DNA. The variable (polymorphic) nature of the STR regions examined for forensic testing intensifies the discrimination between one DNA profile and another.

For example, the likelihood that any two people (except the same twins) will have the same 13-loci DNA profile can be as high as 1 in 1 billion or higher. The Federal Bureau of Investigation (FBI) has selected 13 specific STR loci to work as the benchmark for CODIS. The intent of establishing a core set of STR loci is to ensure that all forensic labs can establish uniform DNA databases and, more importantly, reveal valuable forensic information.

Suppose the forensic or condemned offender CODIS index will be used in the investigative phases of unsolved cases. In that case, DNA profiles have to be generated by using STR technology and the specific 13 core STR loci chosen by the FBI.

Mitochondrial DNA Review

Mitochondrial DNA (mtDNA) analysis allows forensic labs to develop DNA profiles from the evidence that might not be suitable for STR or RFLP analysis. While RFLP and PCR techniques to analyze DNA extracted from a cell’s nucleus, mtDNA technology examines DNA found in another area of the cell, the mitochondrion.

Old remains and data lacking nucleated cells such as bones, hair shafts, and teeth unamenable to RFLP and STR testing can yield results when mtDNA analysis is done. Because of this, mtDNA testing can be quite beneficial to the investigation of an unsolved case. By way of instance, a cold case log might show that biological evidence in the kind of semen, blood, and hair was collected in a specific case, but that was improperly stored for a lengthy period.

Although PCR analysis occasionally enables the crime laboratory to create a DNA profile from quite degraded evidence, it’s possible that the semen and blood would be highly degraded that nuclear DNA analysis wouldn’t yield a DNA profile. The hair shaft could be focused on mtDNA analysis and are the secret to solving the case.

Finally, it is essential to note that all maternal relatives (by way of example, an individual’s mother or maternal grandmother) have similar mtDNA. This allows unidentified remains to be examined and compared to any maternal relative’s mtDNA profile to help missing persons or unidentified remains investigations. However, mtDNA analysis can be quite beneficial to investigating criminal cases, laboratory personnel should always be involved in the procedure.

Y-Chromosome Analysis

Many genetic markers have been identified on the Y Chromosome, which may be used in forensic samples. Y Chromosome markers aim only for the male portion of a biological sample. Thus, this technique can be quite valuable if the lab identifies complex mixtures (several male contributors) inside a biological data sample. Since the Y chromosome is transmitted directly from a father to all of his sons, it can also trace family relationships among men.

Advancements in Y-chromosome testing may eventually remove the need for labs to extract and separate semen and vaginal tissues (as an instance, from a vaginal swab of a rape kit) before analysis. Cooperative efforts with the crime lab are necessary for deciding which analysis methods will be valuable in a given case. However, it’s important to note that while RFLP and mtDNA testing might be useful for investigating an old case, current DNA databases are being populated with DNA profiles generated with STR analysis. mtDNA and RFLP profiles aren’t compatible with the condemned criminal or forensic indexes of CODIS.

Limitations of using the DNA database

The more data in the forensic and offender index of CODIS, the more powerful a tool it becomes for law enforcement, particularly in its application to the unsolved case investigation. But because many jurisdictions are in the process of creating and populating their DNA databases, a convicted criminal and forensic casework backlogs are built over time and continue to grow for many reasons.

First, as states identify the crime-solving potential of DNA databases, they continue to expand the range of their convicted offender laws, which increases the number of samples to be gathered and tested from the DNA laboratory.

Consequently, over 1 million uncollected condemned offender DNA profiles are”owed” to the machine. An equally valuable but more difficult query to measure is unprocessed casework, which contains biological evidence. This casework backlog might include nonsuspect or unsolved cases that could be examined and solved due to DNA technology advancements.

Statutes Of Limitation

Statutes of limitation may be among the most challenging issues to conquer when examining older cases. Statutes of limitation set time limits under which criminal charges could be filed for a specific crime. These statutes are made for protecting people from using proof that becomes less reliable as time passes.

By way of instance, witnesses’ memories fade as time goes by. However, though some evidence, like eyewitness accounts, can lose trustworthiness with time, DNA evidence can determine truths 10, 15, even 20 years after the crime is committed.

States are starting to realize that the reliability of DNA technology may demand the reevaluation of statutes of constraints in the filing of cases.

Database Expansion

The use of DNA proof and condemned offender DNA Databases has expanded significantly since the first U.S. DNA database was made in 1989. However, local and state DNA databases established in the early 1990s comprised only DNA profiles from sex offenders and convicted murderers. The undeniable success of DNA databases has led to a national trend toward database growth.

All states require at least a few convicted offenders to give a DNA sample to be taken for DNA profiling. In 2000, the Federal Government started requiring certain offenders convicted of Federal or military offenses to also provide a DNA sample to the offender DNA database. Knowing that the DNA database’s effectiveness depends on the volume of information in the forensic index and the condemned offender index of CODIS, many states are changing their database exemptions to include less violent offenders.

Many states are enacting laws to require all convicted felons to submit a DNA profile into the State database. The tendencies for States to include all convicted felons in their databases dramatically increases the amount of condemned offender DNA profiles against which forensic DNA evidence can be compared, hence making the database system a more effective tool for law enforcement.

New lawful approaches DNA technology and DNA databases have supported the development of new approaches to old cases. One such system is that the filing of charges by the “John Doe” warrant. These warrants are based on the special DNA profile collected from the investigation of unsolved crime scene evidence.

However, John Doe warrants are traditionally registered based on an unnamed defendant’s physical description or an alias. Researchers and prosecutors are currently filing charges using the defendant’s DNA profile as the identifier. This advance approach has allowed charges to be registered that toll and allow old cases to be prosecuted when the individual matching the John Doe DNA profile is recognized. John Doe DNA warrants are just one way to enable cases to remain active, providing them the opportunity to be solved through the DNA database in the future.

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