In announcing the decision this week to drop all the charges against Adnan Syed, Baltimore State’s Attorney Marilyn Mosby brought up the results of touch DNA testing on a skirt, pantyhose, jacket and pair of shoes.

Mosby said the examination did not recover any DNA from the skirt, pantyhose and jacket of Hae Min Lee, 18, Syed’s ex-girlfriend and classmate at Woodlawn High School, whose body was found in Leakin Park in Baltimore in 1999. But the testing revealed that there was a mixture of DNA from multiple people on both her shoes.

“Most compelling,” Mosby said on Tuesday at a news conference, “Adnan Syed, his DNA, was excluded.”

Touch DNA — also referred to as trace DNA — simply refers to the idea that people can leave behind genetic material on items that they’ve touched or handled, as opposed to DNA taken from bodily fluids, such as saliva, blood or semen.

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Mark Perlin, chief scientist and executive at Cybergenetics, a Pittsburgh company that developed advanced DNA software called TrueAllele, said most DNA evidence consists of a mixture of two or more people.

With the modern software, Perlin said, it does not make a difference how DNA got onto a piece of evidence. If it’s present, he said, scientists can analyze it.

“Touch DNA makes up much of DNA evidence,” Perlin said. “Handguns. Objects. Clothing. Whenever DNA is not a bodily fluid. But there’s no problem with it. It’s just DNA.”

Even a few dozen human cells, he said, can produce a huge amount of information.

He said it’s critical to see a case report to understand what data the laboratory generated and how it interpreted that information.

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If you want a scientist to tell you what the science has found, you have to see the report,” Perlin said.

Emily Witty, a spokesperson for the Baltimore State’s Attorney’s Office, said it is not releasing the report at this stage of the investigation. Baltimore Police and prosecutors are re-examining the killing.

Baltimore State’s Attorney Marilyn Mosby on Tuesday said she had directed prosecutors to drop the case against Adnan Syed, the subject of the hit podcast “Serial.” (Ulysses Muñoz/The Baltimore Banner)

Syed, 41, was found guilty in Baltimore Circuit Court in 2000 of first-degree murder, robbery, kidnapping and false imprisonment, and sentenced to life in prison plus 30 years. He has always maintained his innocence.

His conviction received international attention in 2014 with the release of the podcast “Serial.” The HBO documentary series “The Case Against Adnan Syed” and the podcast “Undisclosed” have also examined his case.

Circuit Judge Melissa M. Phinn last month granted a motion from the state to throw out Syed’s conviction and ordered his release from prison.

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In the motion, Assistant State’s Attorney Becky Feldman, chief of the Sentencing Review Unit, wrote that an almost one-year investigation had discovered that prosecutors did not turn over exculpatory evidence and uncovered information about two potential alternative suspects.

Feldman reported that she and Syed’s attorney, Assistant Public Defender Erica Suter, director of the Innocence Project Clinic at the University of Baltimore School of Law, also found “significant reliability issues regarding the most critical pieces of evidence at trial.”

Prosecutors had 30 days to either schedule a new date for trial or drop the case.

Patricia Cummings, the former supervisor of the conviction integrity units in the Philadelphia District Attorney’s Office and Dallas County District Attorney’s Office, said the legal question, given the procedural posture of the case, had not been whether Syed was innocent.

Mosby, she said, had to decide whether prosecutors possessed reliable evidence and whether there was enough to prove the case beyond a reasonable doubt.

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Because prosecutors withheld exculpatory evidence, Cummings said, there’s no question that it was a case of a wrongful conviction. She said there is no universal definition of exoneration.

The National Registry of Exonerations, though, generally states that an exoneration takes place when a person who’s been convicted of a crime is “officially cleared after new evidence of innocence becomes available.”

Syed, she said, fits the definition of a person who has been exonerated. But Cummings said there has not been a judicial finding of actual innocence.

In Maryland, people have to persuade an administrative law judge that there is clear and convincing evidence that they are innocent to receive compensation from the state.

“The system is not quite that black-and-white,” Cummings said. “You have those in-between, or you have those resolutions that aren’t nice and neat or juicy, like innocent or guilty.”

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