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CODIS - DNA Database Program
The Combined DNA Indexing System (CODIS) integrates forensic science and computer technology into an effective tool for solving violent crimes. CODIS enables state and local crime labs to search DNA profiles from unsolved cases against DNA profiles from solved cases as well as convicted offenders. When a DNA profile is obtained, it is stored in one of two indices: the Convicted Offender Index or the Forensic Unknown Index.
The Convicted Offender Index contains DNA profiles from individuals convicted on or after January 1, 1996, of any offense from a list of 17 violent crimes, expanded to include all Class A, B, and C felonies in October 2001. The Forensic Index contains DNA profiles developed from crime scene evidence that purportedly belongs to the perpetrator of the crime (we do not enter DNA profiles belonging to victims or parties other than the supposed perpetrator). The CODIS software compares the evidentiary DNA profiles to the convicted offenders, as well as comparing DNA profiles between cases. Matches to convicted offenders can provide leads to investigators, who must then obtain a known reference sample from the offender to confirm the CODIS hit. Matches made between evidentiary DNA profiles in the Forensic Index can link crime scenes together, possibly identifying serial offenders. Based on these types of matches, police can coordinate their respective investigations, and share leads they have developed independently.
The significance of the CODIS system is determined by the assistance it provides law enforcement personnel as well as the number of "hits" it will generate. Maine has had hundreds of CODIS hits. An example of multiple hits to a single perpetrator starts in early 2000, when an elderly woman was sexually assaulted and burglarized in her home in Portland, Maine. At the time of the attack, the woman was terrorized, not knowing who her attacker was. A few months later, a second elderly woman was attacked and sexually assaulted in her home in South Portland. These cases were examined separately at the crime laboratory, but the DNA profiles obtained from biological evidence left at the two crime scenes were found to be a match through CODIS. This profile was stored and searched in the CODIS database with no hits for the next few months.
In an apparently unrelated incident, a young woman was attacked and sexually assaulted in her home in York County. This attack appeared dissimilar since it occurred in a different county and the victim did not fit the same age group of the previous victims, but the DNA profile obtained from the evidence was found to match the DNA profiles obtained from the other two rapes. The younger victim was able to focus on her attacker, getting a description and a first name. This information was relayed to the investigating agency, and through their investigation they were able to develop a suspect and obtain a known reference sample directly from Michael Chase. This sample was compared to all the rapes and found to be a match. When the case for the first victim went to trial, Michael Chase was found guilty. He then plead guilty to the sexual assaults of the first two women and was sentenced to 33 years for each of the attacks, to be served consecutively. Case-to-case hits in CODIS indicated there was a serial rapist in southern Maine and proved to be a critical part of convicting and sentencing Michael Chase to a total of 99 years of imprisonment. Afterwards, CODIS linked Michael Chase to two additional sexual assault cases, one in Old Orchard Beach and another in Boston, Massachusetts.
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