Test case

Suffolk County will be the first in the state to use the latest form of DNA testing in criminal trials. What took so long?

Cityscape by Sarah McNaught

Powder fingerprint kits and white chalk outlines at crime scenes may soon be a thing of the past in Suffolk County.

After six years of contradictory courtroom rulings, Suffolk has become the first county in Massachusetts to allow two of the newest forms of DNA testing as evidence in criminal trials.

Within the next few weeks, 29-year-old Vao Sok is slated to go on trial for the 1992 kidnapping, rape, and murder of a young Revere girl. Thanks to a May 8 decision by the Suffolk Superior Court, this trial (and two other upcoming cases) will include scientific evidence obtained through three different types of polymerase chain reaction (PCR) testing -- a cheaper, faster type of DNA analysis that can sometimes produce results where a better-established method, called restriction fragment length polymorphism (RFLP), cannot.

The move is long overdue. Although Massachusetts has received national acclaim for its law enforcement, this state is the last in the country to admit all three forms of PCR testing as evidence in criminal trials. Some officials say the commonwealth is lagging behind because it has no state forensic labs equipped to conduct DNA analysis.

First used in England, DNA testing -- which compares a defendant's genetic makeup with that of bodily fluids or other material from a crime scene -- appeared in American court systems more than a decade ago. According to Carl Ladd of the Connecticut State Forensics Lab, the DNA extracted from samples of blood, semen, hair, tissue, bone, saliva, or urine is amplified and placed in a color developer that shows different DNA components. If the samples appear to match, analysts calculate the odds of more than one individual's having the same genetic profile.

PCR testing is in many ways easier to use than other forms of DNA analysis. The more widely used RFLP analysis requires a fairly large amount of fresh genetic material -- a quarter-size blood stain or a dime-size semen stain. But the PCR tests, Ladd explains, can be used on older evidence and can work on samples as small as a strand of hair or saliva left on a cigarette butt. And whereas RFLP can take months, PCR analysis can be completed in 24 hours.

There are three types of PCR testing: DQA1, which was introduced in 1990; polymarker, which entered the forensics scene in 1994; and D1S80, which also appeared in 1994.

DQA1 has been used here before, but the other two forms of PCR testing will make their Massachusetts debuts in the Vao Sok case, says Ladd. Indeed, Sok's alleged slaying of five-year-old Anmorian Or has brought the debate over the newer DNA testing techniques to the forefront of the state judicial system.

Or, a kindergartner at the James A. Garfield School in Revere, was last seen playing with friends outdoors on May 15, 1992. The next day, her father found her in a vacant apartment in the building where the family lived. Bloody and unconscious, the child was rushed to Massachusetts General Hospital, where she was on life support for three days before she died. Autopsy results revealed that Or had been raped and suffocated.

Sok was arrested as a suspect in Or's murder on May 22, 1992; at the time, he was awaiting trial for the alleged kidnapping and rape of an eight-year-old girl in Lynn. Sok was acquitted of those charges in 1994, but he has been held without bail for the past six years pending the Or homicide trial.

"Sok was questioned over a three-day period prior to his arrest," explains Dave Meier, the chief of the Suffolk County DA's homicide unit and the prosecutor for the Sok case. "During that time, physical evidence was removed from his home. Hair from his head and pubic area, and blood, was also collected for a battery of tests." Prosecutors hope that PCR analysis of these samples will tie Sok to evidence found at the crime scene.

The Superior Court's ruling will also allow prosecutors to use the three forms of PCR testing in two other homicide cases. One, expected to come to trial immediately following the Sok case, involves the 1993 murder of New England Conservatory of Music student Allan Hill, who was fatally stabbed as he left his South End apartment to return bottles at a local convenience store. James Ware and Herdius Evans were charged with the murder of the 21-year-old clarinetist, who had been set to graduate that June. The third case is the 1994 murder of Zachariah Johnson, a 68-year-old Dorchester resident whose body was discovered in an alley beside his Washington Street apartment. Henry Juan Williams was charged with stabbing Johnson to death.

In all three cases, there were no eyewitnesses, and the evidence at each scene was found in such small quantities that it was difficult to conduct conclusive tests using older forms of DNA analysis. PCR testing gets around that problem.

Yet despite its potential for helping to solve difficult cases, PCR testing has been controversial. According to Ladd, PCR is not as precise as RFLP. With RFLP results, the chance that two DNA profiles will match is thought to be one in a billion; if a suspect's DNA is found to match the genetic profile of the crime-scene evidence, the evidence for guilt is persuasive. With the oldest form of PCR testing, on the other hand, the odds of finding a match can be as high as one in five. When all three PCR tests are used together, the figures are closer to 1 in 100,000 -- much better, but still not as good as the RFLP statistics.

Still, more-traditional testing techniques are even less accurate. "Blood grouping and fiber matching are two of the oldest forms of testing done, and often those results only narrow the number of potential suspects to 45 percent of the population," says Ladd.

The accuracy of the tests themselves was not the only reason Massachusetts delayed accepting PCR evidence; the reliability of the lab that conducted the tests was also an issue. "Unlike many other states, Massachusetts does not have a state forensics lab equipped to conduct complicated DNA analysis of evidence," says Suffolk County DA Ralph Martin. Instead of relying on a state lab, the DA's office hires private labs to conduct testing.

Ladd, who testified in favor of PCR testing before the Suffolk Superior Court, says that's part of the reason for the state's delay in accepting the new techniques. "These tests have been used in trials in every other state in the country," he points out. "The admissibility challenges we just settled a few weeks ago were settled nationwide three years ago. The use of private labs leaves the reliability of the tests open to scrutiny, there is no question about it."

In addition to the cases mentioned in the Superior Court ruling, the decision could have implications for the high-profile case of slain assistant attorney general Paul McLaughlin, who was shot at a West Roxbury MBTA station in September 1995. On May 1, a .357-caliber handgun believed to be related to the murder was found under a trailer behind a West Roxbury home. The gun was located just 10 feet from where a blood-stained sweatshirt and saliva-soaked bandanna had been found shortly after the killing. Prosecutors hope PCR testing will link the weapon more strongly to suspect Jeffrey Bly, who was charged in February with shooting McLaughlin.

PCR testing has already cleared another suspect in the McLaughlin murder. It is not unusual, says Ladd, for PCR analysis to prove a suspect's innocence: "Many times people become suspects because of less-refined forensics tests and are cleared when more precise evidence like DNA testing is conducted." In New York, he says, Project Innocence -- organized by attorneys Peter Newfeld and Barry Scheck, of O.J. Simpson fame -- has gotten 40 people off death row because of follow-up DNA testing.

Whether it's used to catch the guilty or set the innocent free, DNA testing will eventually replace most traditional forms of forensic testing. Massachusetts will be at a serious disadvantage unless it creates the necessary facilities. Martin says his office has made several requests to the Department of Public Safety for the creation of a state DNA forensics lab; he also applied for grants from the federal government. The proposal is still under consideration, however, and the grants were denied.

Sarah McNaught can be reached at smcnaught[a]phx.com.