How an Oak Ridge National Laboratory scientist helped solve a murder

Scientific methods and techniques developed and used at Oak Ridge National Laboratory have been helpful in the detection and investigation of several crimes.

Madhavi Martin, leader of the Biomaterials and Biomass Characterization Group in ORNL’s Biosciences Division, has used laser-induced breakdown spectroscopy (LIBS) to provide useful forensic evidence in several cases. Her work for one case led to the conviction of a man who murdered the mother of a baby.

At her recent talk to Friends of ORNL, Martin told how she used LIBS to identify and quantify the chemical elements in logs from Texas in 2004 without knowing why a University of Tennessee professor asked her to do the analysis. Her findings helped lead to the conviction of the man who murdered the 20-year-old mother of a three-month-old daughter.

Here’s an edited version of the story she told FORNL.

The young women disappeared at midnight and left the baby alone in the house. Her husband came home and called the police. He said he didn’t know where she had gone and why she left the baby alone. A police detective found out that the couple had been having arguments and were planning to get a divorce.

Then the skeleton of a young woman was found almost completely burned near a state park close to a small town in Texas. The body could not be identified indisputably because the missing woman had no teeth records on file. But some partially burned logs were found near her body. That potential evidence suggested to the detective that the murderer had chopped down a tree from the state park’s wooded area and had tried to set fire to the logs to aid him in burning the body of the woman he had killed.

Later in the day of the murder, a well-attended outdoor barbecue was held near the home of the dead woman. Her husband, whom the police suspected was the murderer, had attended this event. The police collected the burned logs from the murder site and from the barbecue pit. Noting that the mesquite samples from both sites looked similar, they sent the partially burned logs to the University of Tennessee’s expert in dendrochronology, who often can tell if various wood samples come from the same tree by counting tree rings.

“The tree rings were not well formed in the mesquite logs sent to him, so he was having problems determining if all the logs came from the same tree or a group of similar trees,” Martin said. “So, by using Google he looked for a wood chemistry expert and found me.”

He asked Martin if she could analyze the element content of wood samples and determine whether they were all similar or dissimilar. He did not tell her that her findings could be used to help identify a murderer. She replied that she had just received seed money to pursue wood chemistry projects.

Her manager gave her permission to use LIBS to analyze 13 bulky logs delivered from UT at Knoxville to ORNL. She also unknowingly received control samples – mesquite logs sold by a store for use in home fireplaces. It took her six months to get her final results.

Martin called the UT dendrochronologist and told him, “I have good news and bad news.” He asked for the good news. “I finished the analysis of all the logs, and it took me six months,” she said. “It was hard work and I didn’t have a good stage for them. I had to keep turning them around to scan them properly with the laser. I’m so glad I’m done.”

“What’s the bad news?” he asked. “The logs all look the same except for one or two and I don’t know why they’re different,” she said. “That’s actually good news,” he said. “Let’s meet so I can see your data and tell you the whole story behind this project.”

Martin learned that her data would likely be used to help solve a murder mystery in Texas. The UT dendrochronologist did statistics on her data. “He found that it was 99.9% certain that all the wood, except for the control samples, came from the same tree or clump of trees in the state park, where the crime was committed,” Martin said.

Another one of her important findings was that the wood from the state park contained another element not usually found in trees – titanium.

“It turns out that near the park is a factory that produces waste contaminated with titanium that gets into the water and soil in the surrounding region and is picked up by the trees in the area near the factory,” Martin said. “That evidence helped confirm that the wood at the barbecue pits came from the site of the murder.”

After questioning, the police found out that the husband had an alibi that proved he was not in the house when his wife disappeared. Then it was learned that another man was known to have brought wood to the outdoor barbecue.

The new suspect was questioned and told by police that the wood at the barbecue matched the wood at the murder site, indicating it was from the same tree or group of trees. The murderer eventually confessed to committing the crime. He was tried and convicted.

“It was a such a sad story,” said Martin, noting that the baby who lost her young mother to a crime is now 20 years old.

More detective work by Martin

Martin has used LIBS to do analyses of counterfeit currency for the CIA and of carpet samples from the trunk of Casey Anthony’s car. The forensic evidence was obtained for the trial of Casey Anthony, whose toddler daughter Caylee mysteriously died on July 15, 2008, in Orlando, Florida. The mother, accused of murder and child abuse, was found guilty in July 2011 of four misdemeanors for providing false information to a law enforcement officer. She was acquitted on the murder charge.

In another case, Martin found out why a man who had received a hip implant suffered increasing pain and finally could no longer walk six months after his hip replacement. A surgeon removed the implant and asked police to investigate whether the implant’s materials were responsible for his suffering.

“Nobody wanted to take the blame for what happened to him,” Martin said.

She was asked to use LIBS to determine the elemental contents of the failed implant, which was purported to be made of or coated with titanium oxide. She was given three samples from three different areas of the hip implant.

“We found that the implant contained no titanium and that it was made solely from stainless steel that was leaching toxic chromium and other elements into the victim’s body,” she said.

Her forensic evidence was used in a successful lawsuit against the manufacturer of the failed hip implant.

ORNL scientists can make a difference in many ways.