Under Phase I, the FCC requires carriers, within six months of a valid request by a local Public Safety Answering Point (PSAP), to provide the PSAP with the telephone number of the originator of a wireless 911 call and the location of the cell site or base station transmitting the call.
Under Phase II, the FCC requires wireless carriers [provide] … the latitude and longitude of the caller. This information must meet FCC accuracy standards, generally to within 50 to 300 meters, depending on the type of technology used.
With Phase II, the FCC requires technology to be in place that can pinpoint a phone within 50 to 300 meters, which is better than is possible with Phase I tower technology. Don Lewis, a forensic computer analyst with Lakewood Police Department in Colorado, explains that with some types of phones using GPS information, location distance narrows. “Device applications can record GPS locations which can be more accurate,” Lewis says. “Common applications utilizing GPS include device based cameras. A good example is the iPhone, which records with a high degree of accuracy GPS locations. This GPS data is retrievable in the image metadata.”
Lewis has worked in the Lakewood PD crime lab for 23 years, nine years as a forensic computer analyst including cell phone forensics. He explains that by “reviewing the tower locations and connection times a path of travel can be established.”
Lewis explains that sometimes, the leads are hidden there within data and with closer analysis, can become helpful in a case. Lewis says in a recent case the cell tower data and what the investigators knew about the phone lead them to dig a little deeper. In the case, a phone was found beneath a deceased victim. But cell tower activity continued for days after the scene had been secured (from towers several miles away), confusing investigators. Lewis explains:
“There was some initial confusion by investigators that the phone was still connecting to towers over some distance, in a metropolitan area, while it was under the deceased and saturated in blood. It was found a cloned SIM card was being used in a similar phone. Using cell tower connection data ... we were able to locate the building the subject using the phone was residing in. Cell tower connection times were compared to surveillance video from the building identifying the subject of interest. Forensics from the recovered phone in possession of the subject contained content discussing the homicide.”
Multimedia forensics in question
Three years ago, the National Academy of Sciences reported to Congress that there were flaws in the science of forensics that undermine the unbiased classification that the title “science” requires. Of the many forensic disciplines, DNA was the only area that the report backed as solid. For the others, such as forensic odontology and tool mark analysis, the report gave recommendations from experts in the forensic community on how to strengthen the disciplines (Read the 2009 LET feature, “Flawed forensics?” on the original report at www.officer.com/10233455.)
The 2009 “Strengthening Forensic Science in the United States: A Path Forward” also touched on digital and multimedia forensics. In the report’s conclusion, it states:
(1) the digital evidence community does not have an agreed certification program or list of qualifications for digital forensic examiners;
(2) some agencies still treat the examination of digital evidence as an investigative rather than a forensic activity; and
(3) there is wide variability in and uncertainty about the education, experience, and training of those practicing this discipline.
Similarly, Michael Cherry, president of Cherry Biometrics, a security technology firm, has concerns about the origins of using cell tower evidence in criminal cases. Cherry and his colleagues have served as expert witnesses in cases that challenged cell tower science. In January/February issue of Judicature, the American Judicature Society publication, an article titled “Cell tower junk science” cited three recent cases in which defense attorneys challenged the cell tower pinging evidence and were successful in arousing suspicion amongst others in their effort. “We’re doing this because we think it’s important,” Cherry says. He adds that the firm has background with the cell phone companies and applicable telephone experience. With his knowledge and understanding of the technology, he says “we saw that there were flaws and we went after [cell tower evidence].”