Thursday, December 12, 2013
By DOUG HARLOW Morning Sentinel
SKOWHEGAN - When physical evidence in the 32-year-old murder case against Jay Mercier seemed to bog down in court last month with tire tracks and old photographs, the state still had one trick left up its prosecutorial sleeve: DNA.
Rita St. Peter
HOW DNA IS USED
The past decade has seen great advances in a powerful criminal justice tool: deoxyribonucleic acid, or DNA.
DNA can be used to identify criminals with incredible accuracy when biological evidence exists. By the same token, DNA can be used to clear suspects and exonerate persons mistakenly accused or convicted of crimes.
In all, DNA technology is increasingly vital to ensuring accuracy and fairness in the criminal justice system.
DNA is generally used to solve crimes in one of two ways.
In cases where a suspect is identified, a sample of that person's DNA can be compared to evidence from the crime scene. The results of this comparison may help establish whether the suspect committed the crime.
In cases where a suspect has not yet been identified, biological evidence from the crime scene can be analyzed and compared to offender profiles in DNA databases to help identify the perpetrator.
Source: U.S. Department of Justice website
Investigative work by Maine State Police Detective Bryant Jacques, who collected biological samples from Mercier, and scientists at the State Police Crime Lab in Augusta who analyzed them, allowed prosecutors to convict Mercier of the brutal July 1980 murder of 20-year-old Rita St. Peter.
It was the state's oldest cold-case homicide.
Even so, it's not that rare anymore to get a guilty verdict by a jury in such an old case, says Assistant Attorney General William Stokes.
"We're finding increasing success in some of these old cases," Stokes said.
Even in the 1980s, investigators took fluid samples from rape and murder victims. Samples from St. Peter's body were taken and stored during a time when no one had even heard of DNA.
Those samples were enough to send Mercier, 57, of Industry, to prison for 25 years to life. He will be sentenced next month.
"It's a very satisfying feeling to be able to go to the family of murder victims and to tell them we've had a break in the case," Stokes said. "It's something that they probably never expected; in some instances, they've just given up hope."
Stokes points to the murder trial of Albert Cochran in 1999, when the Attorney General's Office got a conviction using DNA samples taken from murder victim Janet Baxter in 1976.
"That was unsolved for almost 23 years," he said.
There was the case against Thomas Mitchell Jr., who was indicted in September 2006 in the 1983 stabbing death of 23-year-old Judith Flagg in her Fayette home. Like Mercier, Mitchell had been a prime suspect for some time.
DNA found under Flagg's fingernails was linked to Mitchell. After a jury convicted him, he was sentenced in August 2009 to life in prison without parole.
Walt McKee, an Augusta attorney on the board of the Maine Association of Criminal Defense Lawyers, says DNA evidence can work both ways -- it also can clear a suspect of criminal charges.
"I tried a case in Hancock County a couple of years ago where the DNA evidence was really important," McKee said. "It was obtained, it came back and it was not my client's DNA. In fact, no DNA was found, which in the context of that case was crucial, and he was found not guilty."
McKee said DNA evidence in criminal cases changes the game for defense lawyers and how they represent a client. He said it requires lawyers to gain expertise in areas of biological and medical science that most trial lawyers do not have.
"Evidence collection becomes that much more critical, because of the risk of cross-contamination," he said. "It requires a lot more preparation and it certainly has increased the cost of defending a major case where DNA is involved because of the cost of a DNA expert for the defense to at least review the evidence."
Maine went online with its first DNA laboratory in August 1997, replacing the science of serology, examining serums and human tissue fluids under a microscope, hoping comparisons with other samples would stand up in court.
Without the genetic profile of DNA, they often didn't.
Stokes said the Attorney General's Office now has a prosecutor, Assistant Attorney General Laura Nomani, who works only on cold cases. Nomani worked with Assistant Attorney General Andrew Benson in prosecuting Jay Mercier.
Another prominent murder case in which DNA evidence led to a conviction was that of Edward J. Hackett, who killed Colby College senior Dawn Rossignol of Medway in September 2003. Police used a flake of Hackett's skin to link him to Rossignol's car, and in turn to her brutal murder.
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