DNA on weapon and in Rowland’s car is almost certainly Josephson’s, expert testifies

Throughout the trial Friday of Nathaniel Rowland, prosecutors brought forth pieces of clothing, car seats, trash and more that contained what appeared to be blood.

Now, according to one expert from the South Carolina Law Enforcement Division, DNA witness Ryan DeWane, it is all but certain that much of that blood was that of Samantha Josephson, a former University of South Carolina student who was killed while getting into a car she mistakenly believed was her Uber in March 2019.

For example, DNA found on the serrated blade of the multi-tool prosecutors believe is the murder weapon is 6.9 septillion times

more likely to contain Josephson’s DNA than another person’s DNA, DeWane testified.

Septillion is a number with 24 zeroes, according to Merriam-Webster dictionary.

DNA evidence is a measure of probability, DeWane said. Even when it’s a trillion times more likely that a DNA sample contains a given person’s DNA than not, DNA experts do not say DNA samples “match” another sample, DeWane testified.

Similarly high probabilities were found when DeWane tested blood samples from Rowland’s car and items found in the trash outside Rowland’s then-girlfriend’s house. For example, DNA found on the center console of Rowland’s car, the driver seat headrest and the driver seat buckle receiver were all 6.8 septillion times more likely to contain Josephson’s DNA than another, unaffiliated person’s DNA, DeWane said.

DNA found on a glove inside a trash can at Rowland’s ex girlfriend’s house is likely a mixture of 3 people’s DNA, DeWane said. The DNA is 2.2 septillion times more likely to contain Josephson’s DNA than for the DNA to be from three, unaffiliated people. On that same item, the DNA is 5.2 quintillion times more likely to contain Rowland’s DNA than for it to be from three, unaffiliated people, DeWane testified.

While the jury was not in the courtroom, the prosecutors and defense sparred over whether to allow the admission of certain, less conclusive DNA evidence. While the defense argued some DNA evidence would be misleading, Judge Clifton Newman allowed DNA evidence to be submitted, saying the jury could weigh the quality of the evidence on their own.

This story was originally published July 23, 2021 at 5:02 PM with the headline "DNA on weapon and in Rowland’s car is almost certainly Josephson’s, expert testifies."