Accused win right to query forensics

By a 5-4 vote, the court said the Sixth Amendment guarantee of a right to confront witnesses extended to forensic analysis, such as reports that a powder seized by police was cocaine. The ruling invalidates a Massachusetts law that allowed prosecutors to present such evidence without allowing defendants to cross-examine the experts.

Attorney General Martha Coakley, who had argued before the court that the confrontation clause did not apply to such evidence, predicted yesterday that the ruling will result in drug dealers walking free. She said the state does not have enough laboratory analysts to testify in the approximately 60,000 drug cases handled by the courts - about 5 percent of which go to trial - if defendants seek to cross-examine them. If no experts are available, she said, defendants will probably ask judges to dismiss the cases.

“There will be drug dealers who will not be punished,’’ she said. “They will walk out of court.’’

John A. Grossman, undersecretary of forensic science and technology in the state public safety office, said in a recent Globe interview that the cash-strapped state would have to hire 100 chemists at a cost of about $5 million if the court ruled that such experts must be available to testify. Chemists analyze drug evidence in labs at the Department of Public Health, the State Police, and the University of Massachusetts.

The Innocence Project, a national advocacy group that has used DNA evidence to exonerate 240 convicted criminals, hailed the decision, which applies to state and federal courts across the country. The group said that faulty forensic science contributed to about half of the wrongful convictions the organization has helped to reverse.

“This case hinged largely on whether forensic evidence is a matter of neutral fact or is open to interpretation,’’ the group’s codirector, Peter Neufeld, said in a statement. “The Supreme Court strongly rejected the notion that forensic evidence is always neutral and based on solid science.’’

The group filed a brief siding with Luis Melendez-Diaz, whose appeal of a 2004 cocaine trafficking conviction in a Boston court led to yesterday’s decision.

Mary T. Rogers, a Salem lawyer who worked on the appeal, praised the decision and said it will have far-reaching implications on lab reports dealing with alcohol levels in blood, firearms, and other scientific evidence.

Her client, Melendez-Diaz, and two other men were arrested in 2001 in Boston for allegedly dealing drugs and were placed in a police cruiser. After noticing that the three men were fidgeting in the back seat on the way to the police station, officers searched the cruiser and found 19 plastic bags containing cocaine hidden there.

Technicians at the lab at the state Department of Public Health determined that the substance contained cocaine, prompting prosecutors to submit three “certificates of analysis’’ at trial. Melendez-Diaz objected to the admission of the certificates without the testimony of the analysts but was convicted and sentenced to three years in prison. He appealed unsuccessfully to the state Appeals Court, then to the Supreme Court.

Justice Antonin Scalia, writing for the court, said such defendants have a constitutional right to confront lab analysts, in part because the experts may feel pressure to manipulate the evidence to favor prosecutors.

“Confrontation is designed to weed out not only the fraudulent analyst, but the incompetent one as well,’’ Scalia wrote. “Serious deficiencies have been found in the forensic evidence used in criminal trials.’’

He brushed aside concerns by prosecutors and the dissenting justices that making forensic experts available would burden states. He noted that about 20 states, including California, already give defendants some rights to cross-examine lab employees about forensic evidence.

“Perhaps the best indication that the sky will not fall after today’s decision is that it has not done so already,’’ he wrote.

In dissent, Justice Anthony Kennedy wrote that the decision “sweeps away an accepted rule governing the admission of scientific evidence’’ that has been in place for at least 90 years. When interpreting the confrontation clause, he went on, the majority drew no distinction between laboratory analysts who perform scientific tests and conventional witnesses.

“The Court purchases its meddling with the Confrontation Clause at a dear price, a price not measured in taxpayer dollars alone,’’ Kennedy wrote. “Guilty defendants will go free, on the most technical grounds, as a direct result of today’s decision, adding nothing to the truth-finding process.’’

Coakley, who argued the case Nov. 10 in her first appearance before the high court, said she would seek to introduce state legislation to lessen the burden of the ruling on forensic experts and law enforcement officials. Under the bill, prosecutors would alert defendants that the state intends to introduce lab reports into evidence and give the defense an opportunity to forfeit the right to cross-examine them. Some legal specialists say defendants might opt not to cross-examine the experts because such testimony could reinforce the incriminating evidence.

Berkshire District Attorney David F. Capeless, president of the Massachusetts District Attorneys Association, decried the ruling but called it a “Pyrrhic victory for defendants.’’ He said requiring forensic experts to be available to testify will delay trials, which could mean defendants wait in jail longer for charges to be resolved.

“This was simply a technical complaint, which now is going to cause a huge upheaval in the criminal justice system,’’ he said.

The ruling appeared to cut across ideological lines on the court. Siding with Scalia were Justices Ruth Bader Ginsburg, David H. Souter, John Paul Stevens, and Clarence Thomas.

Joining Kennedy in dissent were Chief Justice John G. Roberts Jr. and Justices Samuel A. Alito Jr. and Stephen G. Breyer.

Saltzman can be reached at jsaltzman@globe.com