Officers went door-to-door asking for voluntary samples last week, neighbors said. Two residents who provided samples said investigators told them the DNA was collected in an effort to eliminate suspects.
Experts say elimination samples are collected to help investigators focus on other suspects. Raleigh Police have declined to comment on this part of their investigation into the death of 62-year-old Kathy Taft.
ETA
Googled "elimination samples" and want to read but thought I'd post here at same time.
http://www.dna.gov/postconviction/h...s/pretestingconsiderations/eliminationsamples
http://www.ncjrs.gov/pdffiles1/nij/bc000614.pdf
When DNA evidence is found at the scene of a crime, it can be compared to DNA obtained
from five classes of individuals. First, suspects in ongoing investigations may volunteer to supply
DNA samples, or they can be ordered to give samples by a court or grand jury. For brevity, we call
these suspect samples.
Second, samples may be obtained purely to eliminate an individual as a
possible source of DNA left by the perpetrator of a crime. These can be called elimination
samples.1 Third, victim samples come from victims of violent crimes. Fourth, relatives of missing
persons sometimes provide DNA samples to assist in the identification of remains.2 Finally, DNA
profiles derived from convicted offender samples are routinely checked against crime-scene
samples.
http://homepages.law.asu.edu/~kayed/pubs/genlaw/ncfdna-nor-01.pdf
So it seems they have the perp's DNA and want to eliminate neighbors as suspects?