Blood Spots, Bullets and Burned Buildings

By Andy Fell

The program, the only one of its kind in California, formally enrolled its first 16 students this fall quarter and expects to have 20 by the end of the first year.

David Howitt, who chairs this new graduate group, traces the impetus for the program to the 1995 O.J. Simpson murder trial. In that trial, defense attorneys successfully cast doubt on both the collection and interpretation of forensic evidence, including bloodstains, DNA and footprints. In the aftermath, the California Criminalistics Institute, a unit of the state Department of Justice that provides specialist training for state and local forensic scientists, began looking for academic partners to raise scientific expertise in state and local labs.

“One of the goals is to get more laboratory research in forensic science,” said Fred Tulleners, director of the state Department of Justice’s criminalistics labs in Sacramento and Santa Rosa, who also teaches in the program.

Adding impetus for the program is the need for forensic experts to have higher qualifications. National and international quality standards for forensic labs now require managers and supervisors to hold at least a master’s degree in biology, chemistry or a related area. Until the launch of the UC Davis program, there was no research-based master’s program in forensic science available in the state; UC Berkeley’s program was phased out in the 1970s.

The program is a joint venture between UC Davis and the California Criminalistics Institute. It is run through UC Davis Extension—the campus’s continuing education program— allowing students already working in forensics labs to study part time without maintaining a full courseload.

The institute doesn’t do lab research and cannot award degrees. By working with UC Davis, the institute can gain access to top researchers in basic science and engineering, while the campus gains access to experts in forensic science and to forensic labs to train students. The association between the institute and UC Davis began when Howitt, an expert in how materials are damaged by fires and explosions, met John DeHaan, a state forensics expert who now runs his own consulting business.

“Forensic science” encompasses all legal investigations of crime scenes, accidents and other disasters, both natural and man-made. Investigation and reconstruction of crime scenes is, strictly speaking, the work of “criminalists,” Howitt said. And although crime scene investigation or “CSI” gets the attention, forensic science is also frequently involved in civil cases. For example, when a building burns down, an investigation of the cause—arson or accident, how the fire was set or got started—could be crucial to insurance claims and civil lawsuits.

Sound science

Law professor Edward Imwinkelried, a national expert on DNA and scientific evidence, says changes in the law make it more important than ever to have such a program.

A 1993 Supreme Court decision, Daubert v. Merrell Dow Pharmaceuticals, radically altered the landscape for science in the courtroom, Imwinkelried said. Before 1993, federal and state courts applied a standard derived from the 1923 decision in Frye v. United States. The Frye decision held that scientific evidence was admissible if it used methods “generally accepted” by the scientific community.

In Daubert, the Supreme Court held that scientific evidence must use “sound scientific methodology” to be admissible in court. That gave prosecutors and defense lawyers more scope to bring in new methods, like DNA analysis, before they were widely used, provided it could be demonstrated that those methods were based on sound science. It also allowed courts to test the science behind a new method and make decisions on whether it constituted “sound science” or not.

“You have to lay a foundation at trial, so you need experts who can explain why a technique is sound. The witness on the stand needs to understand and be able to explain scientific methodology,” Imwinkelried said.

The federal judiciary and all but 17 states, one of them California, have now adopted the Daubert standard. But even in those holdout states, common sense leads to the Daubert rather than the Frye standard, Imwinkelried said.

“The nation and California need people with this kind of scientific training,” he said. Investigators and prosecutors, judges and attorneys are concerned about these issues and are learning more and more about science and statistics, for both criminal cases and cases about civil rights or the environment, Imwinkelried said.

“The modern practice of law does not allow you to escape science,” he said.

Cold cases

So keen are some of the participants in the program that they began taking courses well before the first students were formally admitted in fall 2002. Joy Viray ’98, for example, heard about the proposed program and began working toward the degree in 1999.

Viray, who has a bachelor’s degree in genetics from UC Davis, worked in the laboratory of anthropology professor David Glenn Smith both before and after graduation, carrying out DNA analysis on ancient human bones.

Viray spent much of her time in Smith’s lab studying DNA sequences called short tandem repeats in humans and other primates. Short tandem repeats, or STRs, are widely used in forensics labs as markers for identifying individual human DNA.

Viray’s experience working in Smith’s lab made her realize that “what I really wanted to get into was human genetics,” she said. “I’ve been taking all the classes I can take and more than I need.”
Viray now works at the Sacramento County Forensic Services laboratory, analyzing evidence from sexual assaults. She checks for sperm and saliva on swabs taken from victims, their clothing or other items and carries out DNA analysis to provide evidence that could tie a suspect to the crime.
Her work receives a different level of scrutiny and review than it would in a university lab, Viray said. After all, results may make the difference between conviction and acquittal. At the same time, her experience in the anthropology lab taught her to work with samples of unknown age and poor condition.

As part of her degree, Viray plans to conduct a research project at the Sacramento county lab, looking at ways to analyze very small amounts of DNA. Scientists call this “low copy number” DNA because only a few copies of the DNA are available, which occurs, for example, if only a few sperm can be found. In a research lab, scientists can perform analyses on samples as small as a single cell, but they are usually working with samples under ideal conditions.

Many of the samples Viray analyzes come from “cold cases”—assaults that may have happened years ago, when no suspect was found. The state’s Cold Hit project, supported by a grant of $50 million from the governor’s office, was set up to analyze the DNA that had been collected for some of the 20,000 unsolved sexual assaults in California. More than 750 cases dating back to 1994 have been through an initial screening in the Sacramento County laboratory, with DNA profiles being prepared for over 120. To date, approximately 10 percent have come up with a hit: someone already entered in the state’s DNA database.

In some cases with no known suspect, prosecutors are using DNA profiles to file cases against “John Doe” before the statute of limitation can expire. Whether such prosecutions will hold up has yet to be decided by state courts, said Imwinkelried.

Those cold cases sit in freezers in plain white boxes, a victim’s name, a barcode and some other information on the lid. But Viray says she feels she’s helping the women those boxes represent.

“Every day I walk out of here feeling I’ve done my bit for society,” she said.

Sure shot

At the Department of Justice’s Sacramento crime lab, directly across Broadway from where Viray works, Karen Cebra is looking very hard at bullets. She’s working with crime lab director Tulleners on a project to establish an objective basis for matching bullets to the guns that fire them.

Fired bullets have longitudinal scratches, or striae, on them that match the rifling grooves and other features of the gun barrel. While bullet comparison is well established and often called upon in court, the process of making those comparisons is somewhat subjective, Cebra said. To decide if two bullets came from the same gun, the analyst needs to make decisions about what constitutes a line and a match, she said. Lighting and viewing the bullet from different angles can also have an effect.

Fortunately, when a match is found it is usually so clear as to be virtually unchallengeable, she said. But putting those arguments on a firmer statistical basis would still be useful. Cebra’s approach is to start at the same point on each bullet and see how many consecutive striae around the circumference of the bullet match. Some will match by chance, she said, but it’s very rare for a run of consecutive striae to match unless they come from the same gun. “There’s a dramatic difference,” she said.

By working out the statistics behind line counting, Cebra hopes to eliminate the subjective element in bullet comparison. She’s also speculating about automated methods to measure scratches.

“There’s lots and lots of microscope work,” she said.

Although Cebra works surrounded by ammunition and next to a vault filled with guns ranging from pearl-handled revolvers to machine guns and a bazooka, she’s not a hunter and says she had little familiarity with guns before beginning the program. She says she does want to take the Department of Justice’s firearms training.

Cebra became interested in forensics while working in the museum at Michigan State University and then at the California Academy of Sciences as collections manager for birds and mammals. Museum specialists would sometimes get requests to identify or analyze animal traces or remains for criminal or smuggling cases. At the academy, Cebra was once asked to go through a trash bag of bird feathers to find probable cause to search the house of a suspect in a missing-person case. She was able to identify feathers from a number of species, such as bald eagles, that had been illegally poached, allowing investigators to ask for a search warrant.

“Wildlife forensics is the coolest part of the field, but the smallest,” Cebra said. Currently only one government laboratory in the United States does wildlife forensics work, she said, and opportunities in the field are limited. So she decided to broaden her knowledge and experience by enrolling in the UC Davis master’s program.

A toothsome field

San Francisco dentist Roger Kussman feels that he has plenty of life experience to bring to the job, but he sometimes wishes his science background was a little more up-to-date.

“Trigonometry, I haven’t had that in 30 years,” he says, talking about a recent class on blood spatter analysis. As for DNA analysis, he thinks the more recent graduates are a little ahead of him in biology and chemistry. On the other hand, experience and knowing what questions to ask are more important in the field, he said.

Kussman is studying forensics part time while continuing his dental practice. Like Cebra, he says he has dabbled in forensic work within his own specialty, helping the San Francisco coroner on a cold case and going into the field with a police surgeon. But the forensic dentistry field is hard to break into, he said.

Dental records are often used to identify badly burned or decomposed bodies. Bite-mark evidence is also becoming more important in homicide and child abuse cases, Kussman said.

Kussman hopes eventually to work as a field investigator in forensic science. While his first interest is teeth, he finds the other areas “just fascinating,” he said.

From textiles to law

Students taking the full master’s program complete a core of courses on forensic science taught by faculty from UC Davis, the California Criminalistics Institute and other working professionals. They also take a number of elective courses from across the UC Davis curriculum. Those courses can include molecular biology, combustion science, textiles and fibers, population biology, psychology and law.

To graduate, students also have to produce a thesis based on laboratory research, which must be publishable in peer-reviewed journals, forensics expert DeHaan said.

The graduate group in forensic science is also attracting an eclectic mix of faculty from biology, botany, entomology, engineering, chemistry, toxicology and the School of Law, along with humanities departments like psychology and anthropology. Outside experts such as Tulleners and DeHaan are brought in to teach as well.

“By combining the expertise of our faculty with that of the practicing criminalists at the Department of Justice,” Howitt said, “we have been able to bring a wealth of expertise to the program.”

Andy Fell writes about the sciences for the UC Davis News Service. Photography by Debbie Aldridge/UC Davis Mediaworks.