A Jamaica Plain man has been acquitted in a retrial of a cocaine trafficking case that went all the way to the US Supreme Court and resulted in a landmark decision affecting evidence in criminal trials around the country.
A jury found Luis Melendez-Diaz, 32, not guilty this afternoon in Suffolk Superior Court.
Melendez-Diaz's appeal of his 2004 cocaine trafficking conviction led to a ruling by the Supreme Court in 2009 that the US Constitution's Sixth Amendment guaranteed defendants in criminal cases the right to confront forensic experts in court.
The ruling invalidated a Massachusetts law that allowed prosecutors to present forensic experts' reports as evidence without giving defendants the opportunity to cross-examine the experts.
On Wednesday, during Melendez-Diaz's retrial, a chemist from the state Department of Public Health testified that the substance allegedly found in the back seat of a police cruiser with Melendez-Diaz and two other men tested "positive for the presence of naturally occurring cocaine."
The Sixth Amendment guarantees a criminal defendant the right "to be confronted with the witnesses against him."
"He's very thankful he was given a second trial and that the jury got it right," said Margaret Fox, Melendez-Diaz's defense attorney.
She said the verdict was "an enormous relief. It was a case that really seemed to be about guilt by association."
"We're 10 years out from the original incident and the passage of so much time only makes a case tougher to try," said Jake Wark, a spokesman for Suffolk District Attorney Daniel F. Conley.
While Melendez-Diaz may have been acquitted today, he is still currently serving a 10-year sentence for drug trafficking in Plymouth County, Wark said.
Brian R. Ballou of the Globe staff contributed to this report.