Western Massachusetts prosecutors will dismiss more than 5,000 drug convictions tied to former drug chemist Sonja Farak.
She pleaded guilty in 2014 to stealing cocaine from the state crime lab in Amherst, and admitted to tainting drug samples by using them herself -- while on the job.
In Hampden County, the district attorney's office plans to toss 3,940 convictions from juvenile and district court, and are reviewing hundreds of Superior Court cases.
And Northwestern District Attorney David Sullivan said he will dismiss every case Farak touched -- almost 1,500.
Sullivan, whose district covers Franklin and Hampshire Counties and the town of Athol, said he has no plans to re-prosecute any of the defendants.
"So many of the people plead guilty -- I'd say 99 percent, off hand," Sullivan said. "They've done their sentence. They've completed what they needed to complete, and I think it's now time to look forward, and rebuild the trust in the criminal justice system."
The dismissals will take the convictions off their criminal records.
Randy Gioia, with the Committee for Public Counsel Services -- the state's public defenders office -- said having those offenses removed from a criminal record can make it easier for the accused to find housing or jobs.
"They may, in many cases, have an opportunity to begin the process of getting back into society without the burden of having this conviction follow them around for years and years and years," Gioia said.
Gioia also said prosecutors across the state should toss every case Farak was involved with.
In Berkshire County, the district attorney's office said it's looking at more than 600 cases involving Farak, and have yet to decide about any dismissals.