Revealing the chemical fingerprints of a crime
On September 4, 2006, Mark Wangler’s wife Kathy died of carbon monoxide poisoning in the couple’s Bath Township, Ohio, home. Yet, Wangler, who was sleeping in another bedroom, survived.
Detectives who visited the home as a matter of protocol began to wonder why only one spouse died—particularly since Wangler claimed the carbon monoxide accumulated because of a faulty ventilation system on the home’s hot water tank. Suspecting foul play, the detectives ultimately collected ductwork from the home, as well as the hot water tank, vent covers, hoses, carpet, Wangler’s diary, journals and computer equipment.
Then they called the FBI and the U.S. Environmental Protection Agency for help—but neither organization had the specialized knowledge to determine the real source of the carbon monoxide. The EPA told detectives to call Civil and Environmental Engineering Professor James Schauer.
Schauer is an international expert in using chemical tracers to identify sources of air pollution. His research group has analyzed pollutants in samples ranging from air in the Middle East to snow in the Greenland ice sheet.
The Ohio detectives asked Schauer to determine whether high concentrations of motor vehicle exhaust had passed through the Wangler home’s ventilation system. Carbon monoxide itself dissipates quickly; however, Schauer and colleagues at the Wisconsin State Lab of Hygiene documented very high concentrations of soot in the ductwork, carpet and other evidence taken from the Wangler home. They used chemical tracers to analyze the soot and determine that an internal combustion engine was its source.
Schauer wrote a report about the group’s findings and testified at Wangler’s trial in March 2011. Prosecuting attorney Juergen Waldick says Schauer’s contributions were critical. “Schauer’s expertise and the work that the lab did was just essential to ruling out one of the possible defenses they had in this case,” he says.
On March 16, 2011, a jury found Wangler guilty of murdering his wife.