Computer scientist Mark Perlin developed TrueAllele, a computer program
used by law-enforcement authorities to help sift through complex
mixtures of DNA from crime scenes.
A Pennsylvania judge has blocked an attempt by defense lawyers for a
man charged with murder to obtain the source code of a computer program
increasingly used by law enforcement authorities to untangle complex
mixes of DNA found at crime scenes.
Judge Jill E. Rangos said in a ruling filed late Thursday
that defense lawyers for Michael Robinson, who is charged with shooting
to death two men in Allegheny County, Pa., failed to show that
“production of the source code is a linchpin to undermining the
Commonwealth’s case” as it pertains to the DNA evidence.
Requiring the company, Cybergenetics, to produce the source code
could “have the potential to cause great harm” to the company by
exposing its trade secrets, she said. Mr. Robinson’s case was featured
in a November Wall Street Journal story about the software, called TrueAllele.
Kenneth Haber, a lawyer for Mr. Robinson, said he and his co-counsel, Noah Geary, were
considering their next steps, including a possible appeal. Mr. Haber
said Judge Rangos had declined to address their central argument.
“A defendant under the the Sixth Amendment has the right to confront
every witness against him,” Mr. Haber said. “Part of confronting a
witness, especially an expert witness, is to be able to know what that
expert is doing to arrive at their conclusions. Without the source code,
Mr. Robinson cannot exercise his Sixth Amendment right.”
Messrs. Haber and Geary had asked Judge Rangos to allow them to
review the source code under a protective order that would have
prohibited them from sharing it, in order to address concerns by
Cybergenetics about its trade secrets being exposed.
Courts in at least seven states have admitted TrueAllele results as
evidence, against objections by defense lawyers whose clients have been
linked to crimes by the software, which was developed by computer
scientist Mark Perlin.
Law enforcement authorities have turned to TrueAllele to help them
overcome a common hurdle in crime labs: making sense of DNA from
multiple people that commingles on gun grips, clothing and victims. Such
mixtures are often too complex for crime labs to sort, leading them to
declare DNA evidence inconclusive more than half the time, experts say.
After DNA evidence is collected, analysts convert it into signals
that appear as peaks and valleys. Most labs discard signals that don’t
rise above certain thresholds, but TrueAllele uses all the data to tease
apart a DNA mixture, separating the genetic types of each person in the
sample so they can be compared with the DNA of suspects, according to
Mr. Perlin.
Mr. Perlin has offered to let defense lawyers conduct their own tests
on the software to satisfy themselves of its reliability. They have
countered that tests alone can’t reveal what assumptions the software
makes about sample degradation, for example, or how it isolates real
signals from mere noise.
“Judge Rangos concurs with other courts,” Mr. Mark Perlin said in a statement on his company’s website. “Scientists test executable software programs on real data; they do not read source code text.”
Mike Manko, a spokesman for Allegheny County District Attorney Stephen A. Zappala Jr., declined to comment.
In Mr. Robinson’s case, investigators found a black bandanna near the
scene of the killings that a witness said was worn by the shooter. They
sent it to the county crime lab to see if it bore the DNA of their top
suspect, Mr. Robinson. The lab found a mixture of DNA from at least
three people on the bandanna and deemed it too complex to analyze,
according to the January 2014 lab report.
TrueAllele concluded Mr. Robinson’s DNA was on the garment. The
report on the software’s findings described the match as “5.7 billion
times more probable than a coincidental match to an unrelated black
person.”
Subscribe to:
Post Comments (Atom)
0 comments:
Post a Comment