In general usage, DNA is a biological molecule found in nearly every cell of every living organism. Because DNA patterns are nearly unique (shared only in the case of identical twins), and DNA is found in skin, hair, blood, semen and saliva, DNA profiling is an important technique in modern crime investigations.

DNA evidence proved to be quite important in the Duke lacrosse case, most notably on two occasions:

  • when the results of the first rounds of DNA testing came back with no matches to any of the lacrosse players,
  • when it was revealed during a December 15 hearing that subsequent testing ordered by Mike Nifong had found DNA from at least five different unidentified males on Crystal Gail Mangum, and that Nifong had hidden that exculpatory evidence from both defense counsel and from the Court. This was one of the offenses for which Nifong was subsequently disbarred.

DNA evidence played a role at other points in the case, as well, either providing actual evidence in the case or shaping public perception of the case.

Samples taken

DNA samples were taken from several different locations, including what were referred to as the "rape kit items", and from fake fingernails left behind by Mangum in the lacrosse house.

Reference samples

In order to see whether there was a match between the DNA of any of the players and DNA left in any other location, it was of course necessary to take samples of the DNA of all the players (save for Devon Sherwood, who was not white and therefore did not match Mangum's description of her attackers.) DNA samples were taken from all 46 white Duke players due to an NTO (non-testimonial order) applied for by Assistant District Attorney David Saacks. The application included language stating that "the DNA evidence requested will immediately rule out any innocent persons, and show conclusive evidence as to who the suspect(s) are in the alleged violent attack upon this victim."[1] The NTO was almost certainly unconstitutional; the law requires that such an order may not be sought unless there is sufficient reason to believe that the subjects of the NTO could have committed the alleged crime. In the case of several players named in the order including Brad Ross, the police already knew that those players were not in Durham that night and could not possibly have been suspects, yet included them in the NTO. However, all the players cooperated voluntarily with the NTO, several citing the assurance that "the DNA evidence requested will immediately rule out any innocent persons" (which Nifong would later ignore) as their reason for complying with an order they could have challenged.


Another source tested for DNA evidence was a set of fake fingernails that Mangum had left in the lacrosse house. Although the media sometimes erroneously reported that only one such fingernail had been tested, and that the sampling had only been taken from under the fingernail,[2] there were actually at least three fingernails tested, and the swabbings from both the underside and the top side of the nails were all combined into a single sample for testing.

Results of the testing

When the DNA results returned, Nifong initially announced that his office would not release the results or other state evidence, as had been expected: "That's just not how we do business, and I would not anticipate that we would treat this case any differently."[3]

In December 2006, however, it was discovered and publicly revealed that DNA samples from at least four unidentified males had been discovered on the rape kit items and on Magnum's underwear, and that this information had not been provided to the defense. Nifong admitted knowing about those results before the indictments, admitted that they were "potentially exculpatory", and acknowledged that he should have given them to the defense before he signed a May 18 filing claiming "the state is not aware of any additional material or information which may be exculpatory in nature."[4]

Public perception

An example of DNA evidence being used to shape public perception might be an August 02, 2006 story in the Raleigh News & Observer headlined "Two Duke lacrosse DNA tests are positive". The lead paragraph says that investigators "recovered two positive DNA specimens from players who lived at the house". Not until several paragraphs into the story is it revealed that the specimens in question were recovered from the bathrooms of the house where both players (Matt Zash and Dave Evans) lived. Kerry Sutton, acting as attorney for Zash, said, "The fact that Mr. Zash's DNA in any form was found in his own bathroom is evidence of nothing related to his case." Brad Bannon, as attorney for Evans, said, "It seems to me that the state of North Carolina has spent thousands of dollars to prove that a young college man's DNA is in his house."

Nifong's explanations of DNA

After the exoneration of the lacrosse players, Nifong offered some unusual explanations for how the DNA of the unidentified males might have gotten into the locations on Mangum where it was found. Nifong suggested that she might have picked up that DNA from riding in the back of a police car on the night of the party. Still later, during his criminal trial in late August 2007, Nifong would theorize that Magnum's "young son" might be the source of some of the DNA.[5]



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