The state’s highest court yesterday upheld the 2007 conviction of a Dorchester man who shot two people he believed had seen him commit an earlier homicide, killing one and injuring the other, Suffolk County District Attorney Daniel F. Conley said today.

The Supreme Judicial Court unanimously affirmed HELDER BARBOSA’s convictions for first-degree murder, armed assault with intent to murder, assault and battery with a dangerous weapon, and unlawful possession of a firearm. The convictions stem from the Oct. 24, 2004, shooting death of 29-year-old Edward Serret and the non-fatal shooting of another man, then 26.

At trial, Suffolk prosecutors proved that Barbosa shot the surviving victim once in the shoulder and, when he feigned death, turned the gun on Serret and shot him six times, killing him. Evidence and testimony proved that Barbosa continued to beat Serret even as he died of gunshot wounds to his lungs and liver.

Boston Police officers responded to the scene minutes after being dispatched to the Robey Street area, encountering a nervous, sweating, and out-of-breath Barbosa who was dressed in black and fleeing the area. After telling the officers that he was running away from gunshots, Barbosa began backing away from their cruiser and then broke into a run, making it about a block before being apprehended.

When Barbosa was tackled, he refused to produce his hands and began crawling – with one officer literally on his back – toward a nearby sewer grate. Once there, he reached in and dropped a heavy object, which created an audible splash from the catch basin. The object was later recovered from the catch basin and found to be a Bryco Arms 9mm handgun that ballistically matched the projectiles recovered from Serret’s body.

On appeal, Barbosa claimed that, under a recent U.S. Supreme Court decision, his right to confront witnesses against him was violated when the chief of the Boston Police Department Crime Laboratory testified as to her opinion on DNA analysis conducted by a technician no longer employed by BPD. The DNA analysis demonstrated that Serret’s blood was found on Barbosa’s boot and pants.

“We do not give so expansive an interpretation to the Melendez-Diaz decision,” Justice Ralph Gants wrote in the 19-page ruling. “In the context of expert testimony, Melendez-Diaz simply stands for the proposition that, under the Sixth Amendment right of confrontation, the Commonwealth may not offer an expert opinion in evidence unless the defendant has an opportunity to cross-examine the expert …. Because Melendez-Diaz did not purport to change the evidentiary rules governing expert testimony, we held shortly thereafter that a medical examiner may offer an expert opinion regarding a victim’s cause of death and related matters based on autopsy results without having been present for or conducted the autopsy.”

Similarly, where a DNA analyst testifies to her expert opinion regarding DNA results, “the defendant may still, as here, cross-examine the testifying expert as to the risk of evidence being mishandled or mislabeled or of data being fabricated or manipulated, and as to whether the expert’s opinion is vulnerable to these risks,” the court wrote.

Barbosa also claimed that the surviving victim’s testimony regarding the previous homicide should not have been allowed at trial. The trial judge allowed that testimony with repeated instructions to jurors on how they should consider it.

“The record reflects that she appropriately balanced the probative weight of the evidence with the risk of unfair prejudice, and prudently determined that the prior bad act evidence was admissible for a limited purpose only,” the court wrote. “The evidence that Serret and [the surviving victim] had witnessed the defendant shoot someone else was not introduced to show the defendant’s bad character, but to explain why the defendant would decide to shoot Serret and [the surviving victim] two weeks later.”

Assistant District Attorney Elisabeth Kosterlitz of Conley’s Appeals Division argued the case before the SJC. Elizabeth Doherty argued on Barbosa’s behalf.