Silent Witness - Volume 10, Number 2, 2006
Catching Criminals by Investigating Profiles with Allelic Similarities
DNA and Databanks
DNA has become a very powerful tool within the criminal justice system, not only to prosecute criminals, but to investigate or exonerate those suspected or convicted of criminal acts as well. The utilization of DNA as an identifier has had a profound impact on the justice system. The court in California v. Robinson asserted that DNA “…appears to be the best identifier of a person that we have.”1 The Combined DNA Indexing System (CODIS) has greatly enhanced the ability to use DNA evidence for identification. CODIS is computer software developed and distributed by the FBI, that allows laboratories to share and compare DNA profiles with each other. The software allows all uploaded DNA profiles to be searched not only against other known DNA offender profiles, but also against unidentified profiles from crime scene evidence, much in the way AFIS, Automated Fingerprint Identification Systems, searches for fingerprints. The FBI’s national Convicted Offender databank currently holds approximately 3.4 million profiles and the Forensic Index contains about 145,000 profiles.2 Databanks similar to the National DNA Indexing System (NDIS) in the United States are also maintained by foreign countries such as Great Britain and Australia.3
In addition to identifying DNA profiles that match exactly at all 26 alleles, CODIS can also identify profiles that are near-matches or profiles with allelic similarities. This article will discuss what a partial profile is, how it can assist in criminal investigations and challenges to the usage of partial profile matches.
DNA Profiling
Traditionally, when a suspect’s DNA profile is compared to a profile from a crime scene evidence sample, there are typically three possible outcomes. The profiles can “match” (if all 26 alleles are the same), the suspect profile can be “excluded” (if differences are observed), or there can be an “inconclusive” result, which means that for a variety of possible reasons, the offender profile being compared could not be included or excluded as the possible source of the crime scene sample.
A “partial match” is a “moderate stringency candidate match between two single source profiles having at each locus at least one allele in common. (emphasis added) A ‘partial match’ is not an exact match of two profiles customarily used to infer the identity of the perpetrator. A potential familial relationship may exist between the offender and the putative perpetrator”.4 It must be noted that not all close relatives will have one allele in common at every locus.
Partial match profiles can be used to catch criminals because there are allelic similarities among closely related individuals. Therefore, these allelic similarities could mean that the perpetrator of a crime is a sibling or close relative of the partial match profile identified in CODIS. For example, during the course of an investigation, a known suspect profile may be compared to an unknown crime scene evidence sample and no match is found. However, the profiles are determined to be significantly similar suggesting that the true perpetrator may in fact be a relative of the original suspect. This can serve as a useful investigative lead for law enforcement to follow.
Alternatively, an unknown evidence sample from a crime scene may be uploaded into CODIS, and when searched against the offender databank a near match profile is identified. An assumption can be drawn that the partial match profile identified could be closely related to the perpetrator of the crime. The partial match profile may provide investigators with a lead in a case that may have otherwise gone cold and/or identify or focus an investigation toward a potential suspect, thus allowing law enforcement agencies to conserve and streamline resources.
Partial Matches to Catch Criminals
Partial match profiles are controversial because a significant number of individuals might be subject to investigation merely on the basis of being related to a prison inmate. According to the U.S. Department of Justice, in 2002 46 percent of prison inmates had a family member who had been incarcerated.5
Until recently, the FBI did not release the personal information of partial matches. Unfortunately, in some instances, investigations stalled and cases went cold because these potential leads could not be investigated. Releasing the personal information of an individual associated with a partial match profile identified in a databank search has drawn debate at the national level. Consequently, in July 2006 the FBI issued an interim plan for release of partial match profiles and the ability to access the personal information of individuals identified through partial match profiles.
“The Interim Plan for the release of information to an NDIS Participating Laboratory is as follows:
- With the documented concurrence of the prosecutor, the casework laboratory that identifies a ‘partial match’ shall provide the NDIS custodian with a written request for the release of the offender’s identifying information. Such written request should include the statistical analysis used to conclude that there may be a potential familial relationship between the suspected perpetrator and the offender.
- Each request will be reviewed by the FBI’s Office of the General Counsel and the NDIS Custodian for approval ”.6
The Interim Plan will apply to federal investigations and aid law enforcement in “situations where a crime has been committed in one state but the DNA of a potential relative is contained in another state’s database7 ”. “…(T)he FBI will allow state crime labs for the first time to tell investigators the names of people whose DNA partially matches that found on evidence at a crime scene…Police then would investigate the close relatives of the known offender8 ”. The release of partial match information by SDIS for in-state investigations is regulated by the individual states. Currently, most state labs are not reporting partial matches, but the FBI’s interim policy may prompt a change. “…(S)tate labs may opt not to report the match if state law or lab policy prevents them from doing so 9”.
Nationally, the use of partial match profiles for investigative purposes is unsettled. Some states will allow partial match profiles to be generated, for example, New York and Massachusetts.10 But according to the State Police Databank Administrator for Massachusetts, although the technique is legal, the State Police are not using it because the manpower is not available.11 “California’s DNA Database technicians report partial matches that ‘appear useful’ to law enforcement, but they do not actively search for relatives12 ”. “In Virginia, lab examiners are permitted to tell investigators that a crime scene sample might have come from a family member when the DNA near-match is ‘very very close13’ ”. Also, “(b)eginning this year, Florida’s DNA database operators have permitted to give investigators the names of convicted offenders who match a crime scene sample at 21 of 26 alleles14 ”. There are no clear or precise parameters as of yet.
North Carolina used this investigative technique successfully. A woman was raped and murdered in 1984, and Darryl Hunt was convicted and served 18 years in prison. The N.C. Bureau of Investigation performed post conviction testing on the crime scene evidence. The 13 loci STR profile developed from a crime scene sample exonerated Darryl Hunt, but the evidence profile did not match any of the 40,000 convicted offenders’ profiles in the N.C. state databank. The closest match found to the evidence sample was that of Anthony Denard Brown. Anthony Brown was excluded, but his DNA matched the crime scene sample at 16 out of a possible 26 alleles. This partial match led investigators to his brother, Willard Brown. Investigators typed Willard Brown’s DNA from discarded cigarette butts and his DNA matched the crime scene evidence profile at all 26 alleles. He pled guilty to the 1984 rape and murder and was sentenced to life plus ten years in prison.15
Familial Searches
Familial searching also provides investigative leads in unsolved crimes based upon partial matches. Familial searching is a technique whereby a crime scene profile is deliberately run through the offender databank in the hopes of getting a list of profiles that are genetically similar to the evidence and using this information as an investigative lead to interview family members of the near matches.
Familial searches are not done in the United States and at present, the FBI has no plans to adopt this technique. They are being performed in the United Kingdom and Wales through the Forensic Science Service (FSS)/Forensic Intelligence Bureau. These searches produce leads which are used in combination with a variety of other investigative techniques. In 2002, the searches were first applied by the FSS to a 1973 case in which three women were murdered in South Wales. A DNA profile taken from crime scene evidence was used for comparison. The National DNA Database (NDNAD) provided investigators with a familial match to Paul Kappen, which then led them to his father, Joseph Kappen. Joseph Kappen was identified as the rapist and murderer of the three women.
This technique was also used in Cardiff, Wales in 2003 to solve a 1988 murder of a 16 year old girl named Lynette White. Analysts identified a single rare allele within the DNA profile typed from the crime scene evidence. The U.K. National DNA Database searched for individuals with the identified rare allele and it led to a 14-year-old boy with a similar overall DNA profile. Further investigation led police to the boy’s paternal uncle, Jeffrey Gafoor. Jeffrey Gafoor’s DNA profile matched the profile from the crime scene evidence. He confessed and was later convicted of the murder of Lynette White.
Defense Challenges to Partial Profiles Searches
A number of challenges to the investigative use of partial match profiles are beginning to surface. The following paragraphs illustrate some of the challenges currently being asserted.
Minority Groups and the Poor will be Targeted
Concerns have been raised that minority groups and the indigent will be unfairly targeted when looking at partial profiles because these groups are overrepresented in the convicted offender databanks.
When searching a DNA databank, the included profiles are all anonymous. DNA profiles are not identifiable by name, gender, race or any other identifiable traits or characteristics, therefore, no specific person or groups can be targeted. The profile is flagged as a near match solely on the basis of its allelic similarities to a forensic profile. The individual connected with the partial profile is anonymous, unless identifying information is otherwise requested and released.
Wasting Time and Resources
Opponents to this technique claim that law enforcement will waste time and resources following up on a variety of leads, many of which may be false and have no bearing on the case.
When investigating a crime, a variety of leads must be considered and pursued. Some will have merit and others will not. Dr. Fred Bieber, a geneticist at Harvard University and a leading proponent of the cautious application of partial matches for criminal investigative purposes, has said, “(n)ot investigating such leads would be like getting a partial license plate number on a getaway car and saying ‘Well, you didn’t get the whole plate so we’re not going to investigate the crime16 ”.
Genetic Surveillance
Another challenge to the use of partial match searches arises from concerns about of genetic surveillance of blood relatives of convicted offenders. By placing millions of ordinary law abiding citizens under “genetic surveillance,” privacy activists believe this search technique places innocent individuals at the mercy of their blood line.
Conclusion
The partial match profile has great investigative potential, but like any other investigative tool, it must be coupled with other relevant investigative techniques. A balance must be achieved between the protection and security of the community and the privacy rights of the individual. Using partial match profiles for investigative purposes is a technique which has only begun to surface and unfold.
Endnotes
1 People v. Robinson, Sacramento Co. Sup. Ct. No. 00F06871; Pending appeal, People v. Robinson, Case No. C044703, CA Third App. Dist.
2 The approximate number of profiles held within the indexes are current as of June 2006. http://www.fbi.gov/hq/lab/codis/national.htm.
3 See The Forensic Science Service, http://www.forensic.gov.uk (used by police in England and Wales) (last visited: August 2006) and CrimTrac, National Criminal Investigation DNA Database, http://www.crimtrac.gov.au/dna.htm (service used by the Australian police department) (last visited: August 2006).
4 Interim Plan for Release of Information in the Event of a “Partial Match” at NDIS, CODIS Bulletin, July 20, 2006. Full text of Bulletin is available at the end of the document.
5 James, Doris, October 13, 2004, Profile of Jail Inmates, 2002, Bureau of Justice Statistics Special Report, NCJ 201932.
6 Interim Plan for Release of Information in the Event of a “Partial Match” at NDIS, CODIS Bulletin, July 20, 2006.
7 Michels, Scott, July 20, 2006, FBI approves using DNA to find suspects’ relatives, U.S. News and World Report, www.usnews.com.
8 Id.
9 Id.
10 N.Y. Comp. Codes R. & Regs. 9 §6192.3 & Mass. Regs. Code 515 §2.14.
11 Cook, Gareth, May 12, 2006, Near Match of DNA Could Lead Police to More Suspects, Boston Globe, http://www.boston.com/news/nation.
12 Id.
13 Id.
14 Id.
15 Richard Willing, Suspects Get Snared by a Relative’s DNA, USA Today, June 8, 2005 at 1A.
16 Weiss, Rick, Vast DNA Bank Pits Policing vs. Privacy, Washingtonpost.com, June 3, 2006.
DOWNLOAD CODIS Bulletin - Interim Plan for the Release of Information in the Event of a "Partial Match" at NDIS.
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