On July 7, 2010, the man thought to be the Grim Sleeper—Lonnie Franklin Jr.—was arrested by Los Angeles police.  The Grim Sleeper was thought to have been responsible for at least 10 deaths in the south L.A. area since 1985.  But why the nickname the “Grim Sleeper”?   It seems that Franklin Jr. took a twelve year hiatus between killing sprees, thus resulting in him being dubbed the Grim Sleeper versus the Grim Reaper. 

Fortunately for police, the Grim Sleeper wasn’t concerned with making sure no evidence was left at his crime scenes.  DNA evidence was recovered from various murder scenes, and upon testing, was shown to belong to the same individual.  However, at the time the samples were collected, there were no matches in the database.  Since 2008, the state of California has adopted a new method for DNA analysis utilizing what is known as familial DNA.  This process allows analysts to run a DNA sample against the databank while looking for a close-but-not-quite-exact match in violent crime cases. 

Let me give a brief DNA lesson:  When doing a DNA comparison, analysts focus on 13 regions, or loci—as decided by the FBI—to look for what are called short tandem repeats (STRs).  STRs are essentially a sequence of base pairs (comprised of the nucleotides A, T, C, and G) that repeat consecutively at a specific location.  For instance, if you have a sequence at a site reading ATGCTACTACTACTATGA, you will see that the repeating sequence is CTA.  This is the STR in this case, and it repeats four times here.  Now, on a different individual, you would look for that same STR and see how many times it repeats for that person at that same location.  The number of repeats will vary from person to person, thus assisting analysts in making identifications or exclusions.   However, relatives will be more apt to share the same number of repeats at each site.  With familial DNA comparisons, analysts look for such similarities, as well as how frequently a given variation in the DNA may occur.  The lab software can then rank who may be a first-order relative to the individual whose DNA is being run.  In addition, California requires that if the individuals in question are male, the STRs on the Y chromosome must be compared as well, as fathers and sons and brothers should have matching STRs. 

Using this technology, the DNA from the Grim Sleeper cases was run through the database in 2008 with no success.  The DNA was run again in 2010.  This time the results indicated that the Grim Sleeper may be related to Christopher Franklin, a young man convicted in 2009 of a felony weapons charge.  The DNA test and other case information led police to Franklin’s father, Lonnie Franklin Jr.  DNA for the elder Franklin was retrieved from a discarded pizza slice, run against the Grim Sleeper DNA, and was confirmed as a match.  Lonnie Franklin Jr. was arrested and charged with ten counts of murder and one count of attempted murder and is currently awaiting an August 9, 2010 arraignment date. 

For more information, please see the following links: Familial DNA Testing, Serial Killer Snared, No Bail for ‘Grim Sleeper’, Grim Sleeper, and Terror Ended

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