“Time of death?,” is one of the most common phrases medical examiners and coroners hear. Unfortunately, it’s easier asked then answered.
“It’s actually extremely difficult, and it often comes down to the level of experience of a forensic investigator. The decomposition process is highly complex and influenced by a wide range of factors that depend on an individual and the environment in which they die,” said Katherine Weisensee, the chair of Clemson University’s sociology, anthropology and criminal justice department.
With this in mind, as well as her own extensive experience, Weisensee has helped create geoFOR, a mobile app that allows coroners and forensic teams to upload data, observations and photos anytime human remains are recovered. The app’s goal is to capture as much information as possible on body decomposition across a variety of geographic areas. Ideally, after years of data input, the app should contain enough data from diverse locations to provide near-instant estimates of time of death.
There are so many factors that contribute to human decomposition, and very little research has been conducted in the area. For example, according to geoFOR, the sample sizes of past human studies range from 3 to 462. The study with 462 remains examined vitreous humor, which is only useful for postmortem interval (PMI) determinations in a short period around the time of death. The next largest sample size included 140 remains in only indoor settings. Overall, the median sample size among all human studies is 52 and the mean is 86—numbers too inconsequential for developing accurate models to determine PMI. Animals models such as pigs have been used in the past, but they are not a suited proxy.
“You cannot make a valid conclusion without more substantial data, which is why geoFOR has been created,” the app’s website explains. “This application allows [specialists] to help fill this critical gap and gather data from vast regions to improve our known samples to develop more reliable methods of determining time since death.”
Medical examiners, coroners and forensic specialists do have some information regarding the impact of temperature, humidity, elevation, etc., on the human decomposition process, but it all comes from research body farms. There are only 7 body farms in the United States, so in addition to offering limited opportunities for learning en mass, the geographic locations are limited. For example, there’s no information on how soil type and texture, rainfall, or insect activity affect the human decomposition in Wyoming or Washington.
The geoFOR app sits at the intersection of geospatial information and forensic science. Users of the app are asked to input as much information about a crime scene as possible, including clothing, location, insect access, scavengers and obvious trauma. In addition, researchers must upload data regarding the decomposition stage of the remains, gender, estimated age and body type. The app then automatically factors in information from numerous geographical and environmental databases to estimate how the variables observed on the body overlap with geography and environmental factors. The app also has unique features like an automatic temperature calculator that can approximate time of death on-site.
“It’s exciting to see just how geospatial information meets forensic science, and how all of this information can be combined to finally start quickly answering a question that has eluded people for so long,” Weisensee said.
geoFOR is currently being beta tested by multiple South Carolina coroners, and Weisensee has applied for additional funding to disseminate the app to more users. Additionally, the anthropology expert is planning a public version of the app that will allow anyone encountering animal remains, such as roadkill or those found by hikers in wooded areas, to take a photo and input information to add to the database.
“That information will be just as valuable, and of course it’s easier to find animal bodies,” Weisensee said. “From soil and weather databases to the actual human and animal remains, the data is all out there; we’ve just got to start collecting it.”
Photo: The initial stages of decomposition (left) contrasted with the proposed model from data collected in geoFOR (right). Credit: College of Behavioral, Social and Health Sciences at Clemson University.