Case Closed

On the night of May 15, 1991, Kevin Divens slipped into Robert Lucas’ Roxbury apartment from an adjacent fire escape and murdered him as he slept.

But Divens left behind traces of evidence that would eventually lead to his conviction: a trail of his own blood on the fire escape.

Divens was arrested that night when he went to an emergency room with a cut on his hand. Police matched his blood type with the splatters on the fire escape, but because his blood also matched that of about 2 percent of the population, he was allowed to go free.

Fourteen years later, with DNA technology allowing investigators to tie suspects to crimes in unprecedented numbers, investigators went back and linked Divens to the crime.

The Boston Police Department’s crime lab, under the direction of Donald Hayes, plays a major part in solving cases like Divens’.

At the lab, DNA technology has helped convict offenders in 92 cases that had no suspects, in addition to solidifying hundreds of other cases against known suspects.

Lt. Margot Hill, deputy superintendent of the family justice division in the Boston Police Department, has worked closely with both Hayes and the lab.

“That’s where we’re catching criminals today – in the crime lab,” said Hill, who also teaches a police reporting course in the College of Communication.

EXAMINING THE EVIDENCE

The crime lab has two major sections. One deals with bodily fluids and biological matter that are eventually used to create the DNA profiles. The other, the trace evidence section, examines evidence – including paint chips, footprints and hair – and looks for patterns that might help police crack a case.

Senior criminalist Elizabeth Ziolkowski, who is one of two trace evidence examiners at the lab, said her work begins with the scientific method.

“You have a question, and you’re going to use the tools of science – observation, measurement, microscopes and instruments – to tell you as much about the material we’re looking at as possible,” Ziolkowski said.

For example, the lab’s sophisticated microscopes might examine paint chips from a hit-and-run accident to answer questions about the accident, she said.

“How many layers are there?” she said. “What colors are the layers? How thick are the layers? Did it come from the vehicle?”

Criminalists also examine pieces of evidence like glass fragments and fibers that might link a car to the scene.

“We’re using the tools of science to say,’What happened here?'” Ziolkowski said.

In the other part of the lab, DNA profiling helps provide critical information about circumstances surrounding crimes.

“When I started DNA technology, there were little murmurs in 1987,” Hayes said.

However, he said, Massachusetts courts did not start to admit DNA evidence until the mid-1990s.

In the case of sexual assaults, examiners at the lab create a profile from an offender’s genetic material by looking at a particular cross section of DNA. Lab technicians look at 13 specific points on the cross section.

As with fingerprints, only one person possesses a given set of DNA characteristics.

“When we look at these 13 different areas, you’ll have two characteristics that you inherit at each location – one you’ve inherited from your mother and one you’ve inherited from your father,” he said, adding that the process resembles paternity testing.

The profile created in the lab is then compared with those of convicted offenders and unknown offenders to see where cases might be linked, Hayes said.

Linking cases and finding serial rapists through DNA enabled Boston police to convict the man responsible for a series of sexual assaults dubbed the “Ashmont rapes” because they occurred near the Ashmont T station in December 2001, Hayes said.

After being found through DNA evidence, Terrance L. Copeland pled guilty to raping four young women in a six-week period.

If a suspect does not have an existing DNA profile on file, police seek him or her out to obtain a sample, typically by swabbing the inside of a suspect’s mouth, Hayes said.

The process is similar for murder and other cases, he said.

COLD CASES

But ultimately the crime lab, despite the technology at its disposal, cannot solve completely cold cases.

Hayes said he recalls a case several years ago in which he received a call from some detectives in the Chinatown area. A woman – probably a prostitute, Hayes said – had woken up covered in blood.

She was uninjured, but blood was everywhere: on the walls, on the refrigerator, in the kitchen and in the bathroom. The bed had a pattern of a body on it.

But, Hayes said, no body was found.

The case went nowhere because none of the blood matched any of the profiles in the crime lab’s database, and the culprit did not leave any telltale clues behind.

Hayes said advancements in forensic science in the last century have contributed to the sophisticated nature of today’s crime labs.

For instance, practices like blood typing were unheard of when Sir Arthur Conan Doyle wrote his Sherlock Holmes novels more than 100 years ago.

“He theorized about these techniques that could come to play before they were actually used in forensics,” Hayes said.

Forensics were written about even earlier in books from 13th-century China, such as “The Washing Away of Wrongs,” which Hayes has in his office.

“I think for many years, man has been interested in looking at how forensics can play a role looking at crimes and particularly suspicious deaths,” he said.