Charting Crime’s Migration
Richard Lemmon is the crime analyst for Henry County, Ga., a suburb of Atlanta and the third-fastest growing county in the nation. He maintains multilayered maps of the jurisdiction’s precincts, districts, and crime categories, as well as the dates, times, and addresses of specific incidents. In addition, Lemmon retrieves incident reports filed by patrol officers and inputs them into his GIS, which “geocodes” the data, converting the crimes and their locations into graphics that can be overlaid on a map.
Lemmon says he looks for specific patterns and distributes the maps to precincts over the county’s intranet. “This is near real-time crime mapping. I can plot criminal activity as it is occurring, show how it is developing, how it is moving across the county boundaries,” he says.
“If an individual is breaking into vehicles or if there is a series of burglaries, we can see the cluster start and actually watch it migrate into other areas,” Lemmon adds. “From each event, we can collect pieces of information, including date, time, location, and add these to the MO used.”
The maps created by Lemmon help Henry County law enforcement determine whether they’re dealing with one or more perpetrators and where to allocate manpower to catch or at least deter offenders working in a particular area. “Since we can see crime patterns developing, our response times are now much faster than they were before we had this capability.”
Henry County’s population has jumped from 58,741 in 1990 to more than 119,000 today. And along with the boom in residents, the county has seen a proliferation of new roads, housing, and community institutions like schools and firehouses. Naturally the police have to stay on top of these changes. The county provides Lemmon with monthly updates that he inputs into his GIS, ensuring that his maps are current.
The Lincoln (Neb.) Police Department uses a GIS system to track crime trends throughout the city. Lincoln PD’s computer crime-mapping system includes geographical information on incidents dating back to 1980, and it helps intelligence officers identify relations between crimes.
Eye in the Sky
In 2002 the Seminole County (Fla.) Sheriff’s Office hired the Veridian Corp. to track individuals on pre-trial release with its “VeriTracks” GPS program and compare their movements with the county’s crime incident reports.
At first glance, this is nothing new. Law enforcement has used electronic monitoring for years. And many agencies still use the conventional monitoring system that requires a radio transmitter built into an ankle bracelet to confirm that a detainee is within his home or other pre-authorized area.
GPS systems work pretty much the same way. For example, GPS-monitored detainees wear an ankle bracelet; however, now they can be tracked just about anywhere on the earth’s surface. Although GPS is not yet as accurate as the example given in this article’s opening scenario—for instance, it only works outdoors—it’s clearly arrived as a crime-fighting tool.
Seminole County is one of the first jurisdictions to combine GPS monitoring with crime mapping. “Today, more than ever, it is critical that police and probation professionals have at their disposal tools to remove the anonymity that most individuals on supervision enjoy,” says Seminole County Sheriff Don Eslinger. “This system reminds them that we will know if they are committing new crimes, and we will not tolerate their criminal activity.”
VeriTracks monitors an individual’s movements throughout the day then plots his or her locations on computer maps of crimes in the last 24 hours. The sheriff’s office can access the system directly. It also receives automatic e-mails when the system red-flags a defendant for being near a crime scene or entering a location that’s been declared off-limits to him, such as a suspected pedophile who’s been ordered to keep away from a school zone.
A growing number of police agencies also use GPS to better protect their officers and deploy them more efficiently. Both the Suffolk County (N.Y.) Police Department and the Hernando County (Fla.) Sheriff’s Office have implemented automatic vehicle location (AVL) systems that map the precise coordinates of each patrol car. Dispatchers can monitor real-time movements of their fleets, and deploy the closest units to an emergency or crime scene. And should an officer need backup, the dispatcher instantly knows where to send it. AVL also gives police managers a strategic tool by providing an overview of deployments so manpower can be evenly distributed or concentrated in hot spots.
This crime map created with ESRI software shows hot spot analysis of auto thefts in Redlands, Calif.
The Duval County (Fla.), Sheriff’s Office recently teamed up with Harris Corp. to build a three-dimensional “virtual” model of Jacksonville Landing, a popular shopping and entertainment complex overlooking the St. John’s River in Jacksonville. The model provides an enormous amount of detail compared to a traditional paper map or even a computer-generated “flat” map. Deputies can view the complex from different angles and see its exits, windows, and other chokepoints. They can also retrieve floor plans for facilities within the complex. For law enforcement and other emergency workers responding to a crisis, this information could prove priceless.
Crime mapping has evolved from a statistical exercise into an intelligence tool that police can use to prevent crimes. And the technology and its application are gaining acceptance nationwide.
But the most important thing cops need to know about crime mapping is that it does not automate policing. The most sophisticated crime analysis data means little if it’s not acted upon by trained, responsible professionals. Consider the following computer-age cautionary tale. When convicted rapist Lawrence Napper was paroled in April 2000, he was placed in a GPS-monitoring program in Texas. The technology—ankle bracelet, receiver, computers, and of course those satellites circling the globe—did exactly what it was supposed to. It followed him and it logged his every move. Yet, over the course of nine months, Napper violated his parole more than 400 times by entering zones restricted to him, including schools and playgrounds. He even drove around Texas Southern University, the same place he’d once kidnapped and raped a student. And Texas officials did nothing. Consequently, in February 2001 Napper abducted and sexually assaulted a six-year-old boy.
This tragedy could have easily been prevented had trained law enforcement personnel been monitoring Napper’s movements and reported his parole violation to officers in the field. The message here is simple: All the crime-mapping technology in the world is useless if no one acts on the intel that it provides.