Prosecutors are scrambling to determine how many cases may be compromised by suspected mishandling of drug evidence at a state crime laboratory, where a former chemist is under criminal investigation.
Norfolk County prosecutors said Friday the apparent lapses already had forced them to drop charges in a number of cases.
“I’m not going to win cases through some kind of underhanded or constitutionally violative process,’’ said Michael Morrissey, the district attorney in Norfolk County. “I respect the Constitution.’’
In February, the state’s public health department notified Morrissey it was investigating a “possible breach in protocol” regarding 90 drug samples from Norfolk County that had been tested at the Hinton State Laboratory Institute in Jamaica Plain. The tests affected 60 criminal cases, he said.
Within 24 hours, he notified defense lawyers of the potential breach, Morrissey said. Some cases were dropped outright, while others moved forward on lesser charges. Cases where drugs were not a central issue proceeded without change.
On Thursday, state authorities announced they had closed the lab, which had conducted about half of the state’s drug testing. Officials say a chemist, who had worked in the lab since 2003 before resigning in March, mishandled drug samples, raising the prospect of tainted evidence and wrongful prosecutions. Law enforcement officials did not name the chemist, but several people familiar with the investigation identified her to the Globe as Annie Dookhan of Franklin.
“We have no idea how far this back this goes,’’ said Anne Goldbach, forensic resources director for the state’s public defender’s office. “It could jeopardize hundreds if not thousands of convictions.’’
Colonel Timothy P. Alben, State Police superintendent, announced Friday night that an additional lab supervisor has been placed on leave.
“This action was taken because the supervisor was responsible for overseeing the work of the lab chemist currently under investigation, and thus was deemed a proper administrative action while the investigation is ongoing,” Alben said in a statement. “There is no evidence suggesting wrongdoing or malfeasance on the part of the supervisor at this time.”
Goldbach said defense lawyers have learned that Dookhan testified under oath at trials without disclosing she had been placed on administrative leave after her alleged misdeeds came to light.
Dookhan could not be reached for comment Friday.
Lawyers are now planning to file appeals, she said. The public defender’s office is launching its own investigation into the matter amid concerns the suspected tampering could date back years.
Deepening the confusion, the scope of the alleged wrongdoing appears far broader than initially believed. As recently as July, Suffolk prosecutors maintained the breach was limited to the Norfolk County cases, but now investigators say it could affect other areas.
“Most, if not all, of the drug cases [in Suffolk County] went to the Jamaica Plain lab,” said Jake Wark, a spokesman for the Suffolk district attorney’s office.
State Police investigators are now determining what cases the chemist handled and will forward the lists to prosecutors, who vowed swift action.
“Our primary consideration is for anyone deprived of fairness in this process, particularly anyone who may have been wrongly incarcerated,” said Michael O’Keefe, district attorney for the Cape and Islands.
After that, safeguards need to be established to “prevent this from happening again,” he said.
Goldbach said the laboratory discovered in June 2011 that the transfer of evidence involving the Norfolk County drug samples was logged improperly. It is not clear why prosecutors were not notified until the following February.
The Department of Public Health oversaw the lab until July 1, when the State Police assumed control. In June, as it prepared to take over the facility, State Police learned of the public health department’s internal investigation into the suspected tampering and launched its own probe.
“During that process, we learned that the alleged improprieties committed by the chemist in question were potentially larger in scope than was previously believed,” Dave Procopio, a spokesman for the State Police, wrote in an e-mail.
He said the evidence suggests the wrongdoing went beyond sloppiness and shortcuts and amounted to potential criminal activity.
John Auerbach, state public health commissioner, said in a statement the department has launched a internal review upon learning of the allegations and placed the director previously responsible for running the lab on leave.
One official briefed on the investigation said it is believed that Dookhan took action to cover up her own conduct in the evidence handling.
Joe Dorant, president of the Massachusetts Organization of State Engineers and Scientists, an employees’ union that represents the laboratory workers, said investigators have told him the alleged tampering was confined to Dookhan.
“They have assured me they aren’t looking at the other employees,” he said.
Dorant said he did not condone the alleged misdeeds, but said budget cuts had left the lab and its staff overwhelmed. Ten lab employees were responsible for 8,000 cases last year and 18,000 samples, he said.
“The backlog has increased dramatically” during the past several years, he said. “Drug analysis is not a simple task. Sometimes, there are consequences to cuts.”