His comments came five days after a grand jury indicted Dwayne McNair, 33, for a second time on charges of raping and robbing the women with another man during two separate incidents in September 2004.

“To the best of my knowledge, this is the first time that any prosecutor’s office in America has attempted to use this [DNA testing] technique in court,” said Suffolk District Attorney Daniel F. Conley on Wednesday.

A Dedham man freed earlier this year while awaiting trial on charges that he raped and robbed two women in Boston in 2004 has been re-indicted in the case, after cutting-edge DNA testing pointed to him as a suspect and ruled out his identical twin brother, according to authorities.


Attempts to reach McNair, who remains free pending his arraignment Monday in Suffolk Superior Court, and his lawyer were unsuccessful.

McNair first emerged as a suspect in the case in 2007, records show, but detectives also learned that he had an identical twin brother. Each sibling’s DNA profile matched a bodily fluid sample that had been collected in connection with the second attack, according to a legal filing.

Since the brothers were identical twins, standard DNA testing could not differentiate between them, and detectives lacked probable cause to arrest either man, the filing stated.

Things changed in 2011, when a second suspect, Anwar Thomas, was linked to both rapes through separate DNA testing. Thomas, who was jailed on unrelated charges at the time, eventually told police that he committed the assaults with McNair, and Thomas pleaded guilty under a “cooperation agreement,” according to court papers.

Based on Thomas’s information, McNair was initially indicted for the rapes in November 2012, and his trial was scheduled to begin on April 29, 2014, but McNair’s DNA evidence remained inconclusive.

On April 2, while preparing for McNair’s trial, prosecutors learned of pioneering DNA testing being done by a German company, Eurofins Scientific, that allowed analysts to differentiate between identical twins.


Prosecutors then requested a delay in McNair’s trial, as Eurofins typically requires 10 weeks to perform the testing in Germany, but a judge denied the bid.

Conley said on Wednesday that, after the denial, he made the wrenching decision to drop the initial indictment and set McNair free while prosecutors awaited the test results. Prosecutors did not want to go to trial with inconclusive DNA evidence that would have allowed defense counsel to point the finger at McNair’s twin.

“That caused me a few sleepless nights, I assure you,” Conley said. “But I felt that this was something we had to do to put our best case forward.”

According to prosecutors, the results from the new tests showed that McNair, rather than his identical twin, committed the rapes with Thomas. Authorities decided to seek the new indictment.

The latest DNA testing cost police and prosecutors more than $100,000, according to Conley.

“It’s very costly,” he said. “But . . . we had two victims who were deeply traumatized and injured by this defendant, so we felt that we should do all that we can to get them some measure of justice.”

He added that an arrest warrant will be issued for McNair if he fails to appear for his arraignment on Monday.

“These were grotesque crimes by violent men who sexually assaulted, robbed, and humiliated these victims,” Conley said.


A hearing will be held where a judge will rule whether prosecutors can present the new evidence in court.

Travis Andersen can be reached at travis.andersen@globe.com. Follow him on Twitter @TAGlobe.