Blood spatters, footprints and bullet casings are all telltale bits of evidence. They can link a suspect to a crime scene.

BY DAWN HOBBS

Killers leave behind more than a dead body.

They frequently leave detectives a blueprint of how the murder was committed.

Detectives from the Santa Barbara Police Department's recently formed Cold Case Unit will use advanced forensic techniques to interpret these blueprints to link killers to unsolved homicides.

One of the 22 cold cases Detectives Tim Roberts and Greg Wilkins are reviewing is the murder of Esther Bueno Taboada.

Police say that the 26-year-old mother of two was stabbed in the neck by her husband in the Sears parking lot in February 1992. She left about a 70-foot trail of blood from his pickup to the spot outside the automotive repair bay where she collapsed and died.

The stain patterns may later be used in court as evidence.

"It will show her direction of travel when she got out of the truck to where she finally dropped," said Detective Greg Wilkins.

The amount of blood at the scene will also show intent — that the wound was meant to kill her — and police hope it will ultimately be linked to the blood found in her husband's pickup, the detective said.

Criminalists from the state Department of Justice laboratory in Goleta frequently respond to murder scenes to analyze the telling blood spatters and other evidence the killer leaves behind.

"Blood-stain patterns are part of a reconstruction of the crime," said Charlene Marie, a senior criminalist. "They can tell you what could have happened and what couldn't have happened."

She works with nine others who re-create and solve crimes through blood-stain analysis; ballistics; the DNA typing of saliva, hair, blood and semen; and the analysis of fibers, footprints and tire prints.

"People who like to do this type of work are attracted to puzzle solving," Ms. Marie said. "And they're interested in seeing that justice gets done — that's what makes it worthwhile."

The popularity of the hit CBS drama "CSI: Crime Scene Investigation," which focuses on forensic investigations, has resulted in the lab receiving dozens of phone calls from people who want to work in the lab — even for free.

HUNTING FOR CLUES      Physical evidence can reconstruct the crime, identify participants and confirm or discredit an alibi.      Evidence typically falls within three distinct categories: body materials, objects and impressions.      Body materials: Blood, semen, urine, saliva, vomit, tissue, hair. Objects: Bullets, discharged casings or cartridges, shotgun shells, live cartridges or rounds of ammunition, shotgun wadding, weapons, firearms, fibers, fabric, cigarette butts, displaced furniture, soil, tools, vehicles, clothing, documents, glass.      Impressions: Fingerprints, tire tracks, footprints, tool marks, bite marks, bullet holes.      The proper collection of evidence gathered at a crime scene is important to the investigation and eventual courtroom presentation. Law enforcement officers are trained to do the following:      Clear the area: To limit the damage or loss of evidence, only essential and authorized persons should be allowed in the immediate crime scene area. The five basic scene contaminators are: weather, relatives or friends of the victim, suspects or associates, curious on-lookers and other members of the police agency and high-ranking officials not directly connected with the case.      Use a systematic approach: Study the whole crime scene first and then systemically cover it so that nonobvious or hidden evidence is not overlooked.      Photograph the evidence: Each piece of evidence should be photographed and the area then marked to show its original location. Package the evidence properly: Each piece should be packaged and identified in separate, clean and proper-sized containers to prevent cross-contamination or damage; be sealed to retain evidence and prevent unauthorized handling; and adhere to the proper chain of custody. SOURCES: Practical Homicide Investigations; Scene of the Crime

"The problem with the program is that they do a lot of things that pushes the envelope a little bit," said Darryl Tate, assistant laboratory director. "Obviously, they have to get the crime solved within a one-hour time frame. Things don't happen that quickly in real life and we certainly don't have unlimited resources to work with like they do."

Local law enforcement agencies usually analyze latent fingerprints, but the Department of Justice lab does just about everything else.

"We're a full-service laboratory," said Mr. Tate. "We do all biological fluids, like blood, semen and saliva, and conventional blood grouping. We also do controlled substance analysis, trace analysis and analysis of impression evidence, like footwear, tire tracks."

The lab, which opened in the early 1970s and services Santa Barbara and San Luis Obispo counties, each year investigates about 2,000 drug cases, 2,000 alcohol arrests and about 200 violent crimes, including homicide, rapes and assaults with a deadly weapon.

When the death is the result of a shooting, criminalist Dave Barber steps in to analyze ballistics.

If a gun is recovered, the first thing he'll do is examine it for trace evidence.

"Was there blood on the gun?" he asked. "If it was a close-range shot there might be blood from the victim on the gun. We also look for hairs, fibers and fingerprints. We sometimes look at the powder residue itself in the gun and see if a similar residue came from the cartridge case."

Sometimes the detectives haven't yet recovered the gun when they ask Mr. Barber to get involved.

"We get guns and we get bullets," Mr. Barber said. "And not all the time do the guns and bullets come at the same time. We have what we call non-gun cases and that's simply a matter of a bullet being recovered from a scene, a body, house, car door, whatever, and they want a list of potential guns."

When a bullet is fired from a gun it has "class characteristics" attributed to it.

Think of it in terms of shoes, Mr. Barber said: "You go out and buy a pair of Vans skateboard-style shoes and all of those shoes will be exactly the same in appearance and have pretty much the same tread."

Likewise, particular makes and models of guns have the same kinds of markings.

"There's lands (the spiraling raised portions in the barrel) and grooves in there," he explained. "There's different numbers of lands and grooves with different manufacturers and models with different widths. We look at the number of lands and grooves and go to the databases of potential guns that have those same characteristics."

If a gun is recovered at the scene or later discovered with a search warrant, the class characteristics of the gun are compared to that of the bullet.

"There can be anything in that gun that can leave a unique mark," he said. "It may not just be the barrel, it may be other parts as well. And we'll look for those marks."

STUDYING EVIDENCE      Fingerprints: Latent prints, which are not visible, are usually found on objects with smooth surfaces or on paper. These prints are left behind when grease or dirt mixes with perspiration and the criminal touches an object. The latent print is developed by a dusting or chemical process.      When a suspect has not been identified, the print is compared to fingerprints of convicted criminals in state and national databases.      When the suspect is known, the forensic investigators look at three levels of detail to match prints: Pattern type, characterized as arches, whorls and loops; ridge flow; and target group for identifiable characteristics.      Next, criminal investigators use ACE-V:      • Analyze — Determine points of comparison, pattern.      • Compare — Take two prints and compare to exemplar prints from the 10-print card.      • Evaluation — Evaluate comparing dot to dot and make decision on match.      • Verification — Independent verification by second and third outside examiner. Everyone must agree before claiming the print is identical.      Footprints: The footprint is the most common impression left at or near the scene of a crime.      Static dust can detect prints on paper or like substances. A metal mylar sheet is then laid over the surface putting a static charge into it.      The print is then photographed using different angles and compared to the suspect shoe through analysis of wear patterns and special nicks.      An impression will then be made on a clear sheet and matched to the suspect shoe.      If a print is in sand or dirt, hair spray will be misted over the impression and then it will be cast using dental stone. SOURCE: Sheriff's Department Sgt. Bob Spinner and Lisa Hemman, senior identification technician; "Practical Homicide Investigation."

Marks are categorized as either striated or impression.

"With a semiautomatic or automatic firearms, we can look at marks on the cartridge cases also," Mr. Barber said. "They can come from the magazine or any place on the cartridge where an impression can be made similar to a shoe print in dirt."

The gun makes marks on the bullets and cartridge because it's a harder material, he explained. A cartridge is generally brass or aluminum, bullets are copper and lead, and the gun is steel.

Mr. Barber uses a microscope that has two eye pieces on it to compare bullets.

"Then you can look at two bullets side by side," he said. "It's really pretty simple."

When analyzing blood-stain patterns, Ms. Marie takes a holistic approach.

"We look at the pattern, we look at the shape," she said. "I look at the size of the droplets. The fine droplets are often from a high impact, such as with a shotgun blast. They're sub 1-millimeter drops. But you need to look at the whole pattern."

Blood spatters will offer different patterns depending on whether the impact — the velocity by which the victim is killed — is high, medium or low.

"Low impact is just blood dripping," she explained. "There's no other action but gravity working. Medium impact comes from something like a bludgeoning. You get a variety of stains and sizes of stains. You get some very small and some very large and, of course, it depends on the blood pool you're whacking into. One thing that helps us with blood stains is that we know the sub-millimeter drops do not travel very far, so they often help us with location."

Just as crucial as where the blood landed is where it didn't.

"We also look for the voids," Ms. Marie said. "We look for the empty spaces because that can often tell you where the attacker was standing. They've left the scene, but they've also left a blank shadow where they were."

In the case of Esther Bueno Taboada, crime scene photographs could be presented to a jury to illustrate the sequence of events.

"Everything in a homicide needs to be factual," Detective Wilkins said. "You need to know as much as you can get about what occurred. It's almost like a painting — a visual picture as to what happened that you can present in court because you don't have a movie."

YOU CAN HELP
If you have information about any of these crimes, you can call the Santa Barbara Police Department's Cold Case Unit at 897-2320 or 897-2426. You can also call the unit's Anonymous Tipline at 569-COPS or send an e-mail to tipline@newspress.com.

e-mail: dhobbs@newspress.com