Prosecutors to retry twin in case marked by DNA limits
Twice since spring 2004, Darrin Fernandez has stood trial on charges of raping a Dorchester woman in her apartment. Both times, the Suffolk County jury failed to reach a verdict for an extraordinary reason: DNA recovered at the scene could have come from his identical twin, as well as from him.
Despite the same outcomes in trials separated by seven months, prosecutors said yesterday they intend to retry Fernandez next month in a case that demonstrates a rare limitation of DNA evidence.
After the most recent mistrial, in February, prosecutors said they were unsure whether they would retry the 30-year-old defendant. A key consideration, Suffolk District Attorney Daniel F. Conley said immediately afterward, was how the alleged rape victim, who now lives in Chicago, felt about returning to Boston.
But despite her anguish at reliving the experience, the alleged victim has agreed to testify that Fernandez climbed a fire escape, forced open a door to her second-story apartment on Peverell Street, and raped her around midnight on April 27, 2001, David Procopio, a spokesman for Conley, said yesterday.
''She has the courage and the will to continue participating," he said.
The Superior Court trial is scheduled to start Sept. 12. Assistant District Attorney Mary C. Kelley, the prosecutor in both trials, and Robert J. Zanello, who defended Fernandez both times, will again oppose each other.
Boston police recovered DNA evidence in semen at the scene, but jurors said after both mistrials that they could not rule out that it had come from Fernandez's identical twin, Damien.
Over the past decade, DNA evidence has become the gold standard for linking suspects to crimes and for exonerating the wrongly convicted. But it has shortcomings, especially in the rare cases involving identical twins who, because they come from the same fertilized egg, have the same DNA.
Dr. Frederick R. Bieber, a Harvard Medical School professor of pathology and a medical geneticist at Brigham and Women's Hospital, said yesterday that he was aware of five to 10 criminal cases in the United States in recent years in which DNA evidence was unable to definitively link a defendant to a crime because the individual had an identical twin.
But forensic scientists may not be stymied for long. A study published last month in the Proceedings of the National Academy of Sciences of the United States of America found that minute chemical changes occur to DNA as people age, and these alterations might enable scientists to distinguish between the genetic material of identical twins.
Christoph Plass, a professor at Ohio State University and a specialist in cancer genetics who participated in the international study, said yesterday that it could take years for researchers to develop a standardized way of detecting such differences. Courts would then have to accept the method as a forensic tool. But he predicted that one day forensic scientists will definitely be able to distinguish between the DNA of identical twins.
In June 2004, days before Fernandez's first trial in the Peverell Street case, Cassandra L. Smith, a professor of biomedical engineering at Boston University, testified at a hearing that she had developed technology to detect differences in the DNA of identical twins if the genetic material has mutated. She said tests could take two years or more to carry out, but Zanello said it was worth delaying the trial that long to make sure the state did not convict the wrong man. However, the Superior Court judge rejected the motion.
Zanello said yesterday he was unaware of the recent international study and was eager to read it.
Nonetheless, he said prosecutors probably would oppose a new motion to delay the retrial to give scientists time to pinpoint ways of detecting differences in the Fernandez brothers' DNA.
Darrin Fernandez is serving a 10- to 15-year sentence in state prison after being convicted of a rape in 2003. He climbed through an open window around 1:35 a.m. on Aug. 26, 2000, and raped a young woman in her parents' home on Hecla Street, in the same neighborhood as Peverell Street.
In that case, the victim identified her attacker as Darrin Fernandez in court and recalled seeing a tattoo that read ''twinz" on his arm. Darrin has such a tattoo, but Damien does not.
The alleged rape victim in the Peverell Street case, which resulted in two hung juries, never mentioned seeing a tattoo.
Jonathan Saltzman can be reached at jsaltzman@globe.com. 