‘‘Everyone is shocked,’’ Warner said. ‘‘We can’t believe it.’’
The year after she started working at the Hinton lab, she married Surrendranath Dookhan, a software engineer also born in Trinidad. They bought a house in Franklin, about 40 miles southwest of Boston, and had a son together in 2006. Branden Dookhan turned 6 this month.
Authorities so far can’t find a motive for Dookhan’s actions other than she wanted to be seen as a good worker, state Attorney General Martha Coakley has said.
But being a good worker became more complicated at the Hinton lab a few years back.
In 2009, a U.S. Supreme Court decision known as Melendez-Diaz grew out of a Boston drug case that said defendants had the right to cross-examine chemists in court who had prepared prosecution reports against them.
The decision meant chemists, including Dookhan, had to spend more time in court and less in the lab to keep up with the demands of the justice system.
‘‘Annie was going through personal problems, then court, and Melendez-Diaz was tough at first on her. In 2009, she had a miscarriage and other personal problems,’’ O'Brien, the co-worker, told state police.
Dookhan already had a reputation as the most productive chemist at the lab, logging such a high volume of samples that colleagues started questioning her work about four years ago.
In 2010, supervisors did a paperwork audit of her work but didn’t retest any of her samples. They didn’t find problems.
Dookhan had to send a resume to prosecutors whenever she testified in criminal cases. In 2010, O'Brien caught Dookhan padding her resume by claiming she had a master’s degree in chemistry from the University of Massachusetts. She took it off her resume but later put it back on, O'Brien told police.
In August, another Hinton chemist told investigators her own monthly sample testing volume dropped from about 400 to 200 after Melendez-Diaz, but talk around the lab was that Dookhan was testing 800 a month.
Another colleague wondered in a police interview whether Dookhan had a mental breakdown.
Dookhan told investigators she was in the process of a long divorce, but there is no record of any divorce complaint filed at the Norfolk Probate and Family Court. She said she wanted to get her work done and never meant to hurt anyone.
After her March 2012 resignation, while facing an internal department probe, Dookhan told a fellow chemist she used to join for after-work drinks that she didn’t want to get her in trouble, too. She told the woman not to call her anymore and to delete all her emails, text messages and records of their phone calls.
A man who worked with Dookhan at Mass Biologics in Boston for a couple years after her college graduation, Aaron Weagle, said she was a pleasant and friendly colleague and not the type of person to fabricate things.
Dookhan’s job then was to perform identification tests on raw materials, what Weagle said amounted to basic chemistry, and was nearly as technical as her work at Hinton. He saw no warning signs, professionally or personally, that Dookhan was heading for disaster.
‘‘She didn’t make up stories to make people like her more. I never saw that,’’ he said.
The chemist he has read about in news on the lab scandal seems like a different person.
‘‘I cannot rectify it,’’ he said, ‘‘with the woman I know.’’