Tracking cellphone activity plays a key role in helping law enforcement officials determine where suspects were before and after crimes were committed.
Using a combination of Esri GIS software and geospatial analysis technology, analysts at the Los Angeles Regional Criminal Information Clearinghouse (LA Clear) are now able to visually display cellphone activity and correlate it with other data and events, such as the issuance of search warrants, to create comprehensive evidence packages.
"Before, low-tech law enforcement analysts would manually enter the latitude and longitude of every call made into a map point system, which was fine for a two-dimensional view of what occurred right at the time of the crime," explains senior lead analyst Toni Nunez.
LA Clear wanted the ability to quickly identify patterns of calls and tie them to criminal activity. That would enable a district attorney to, for example, use cellphone data to show that a suspect had been with someone else at a particular location before or after a criminal incident.
"Now, we're able to merge an entire date range of call records with cell site data and load it into a map and see, for example, that two criminals went and cased a jewelry store two days before they did a smash-and-grab," Nunez explains. Using the new sophisticated 3D mapping system, analysts can show movement and activity over time.
Referring to a recent murder case, Los Angeles prosecutor Lana Johnson notes that "being able to visually show [the jury] that the defendant's phone traveled to the crime scene along with a phone belonging to his fellow gang member was ... key to securing a first-degree murder conviction."