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after over 20 itinerant sex trade workers disappeared during a 30-month
period.

Tactical crime analysis comprises those techniques used to assist inves-

tigators and patrol officers in the apprehension of active criminals (Gottlieb
et al., 1998; see also Reuland, 1997). By comparison, strategic analysis is
concerned with long-term trends and management issues such as the impact
of changing demographics on crime rates. A common problem for tactical
analysis is the prediction of where and when the next crime in a series of
robberies or burglaries will take place. Time, weekday, weather, offence inter-
vals, and other factors are examined to calculate an interval within which the
next crime is most likely to happen. Estimating an offender’s mean “cash
burn” rate (the amount of money stolen divided by the number of days
between successive crimes) can be helpful in determining when a burglar or
robber will likely reoffend. And some success in using chaos theory to predict
a time window for the next attack in a serial murder series has been reported
(Egger, Lange, & Egger, 1996).

The spatial mean and standard distance of the crime sites in a connected

series are commonly used to establish the most probable region for next
offence occurrence. The precision of these pattern recognition methods is
therefore related to the number of previous incidents, leading Gottlieb et al.
(1998) to caution that future crime prediction can be a difficult task. These
methods can be improved somewhat by more sophisticated analyses incor-
porating the influence of such factors as land use, demography, street net-
works, proximity to freeway exits, and other relevant landscape
characteristics. Olligschlaeger (1997), for example, has demonstrated prom-
ise in the application of artificial neural networks to predict locations of “flare
ups” of drug hot spots, using such input data as calls-for-service information,
proportions of commercial and residential properties, and a seasonality
index. The Arson Risk Prediction Index (ARPI) was developed as a computer-
based model to predict arson proneness within Brooklyn neighbourhoods
(Cook, 1985). Early warning signs of significance include number of apart-
ment units, vacancy percentage, serious building code violations, past fires
of unknown origin, and level of tax arrears. The top 50 buildings ranked
with this system captured 30 to 40% of all potential arsons.

The U.S. Forest Service, in collaboration with the Drug Enforcement

Agency (DEA), developed an expert system to locate illicit 

Cannabis sativa

L.

 growth sites within the 856,000 acres of the Chattahoochee National Forest

of Georgia (Fung & Potter, 1992). Relevant variables include topography and
plant sun exposure, soil conditions and water balance, and remoteness, secu-
rity, and privacy. The expert rules were grouped into the categories of topog-
raphy (latitude, altitude, slope, vegetation), soil (nutrient content, soil
texture, pH value), and proximity (distance from settlements, public facilities,

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transportation routes). The system had a reported prediction success rate of
80%.

Crime maps can be descriptive, analytic, or interactive (McEwen & Tax-

man, 1995). While the future of crime mapping is exciting (Sorensen, 1997),
technology, praxis, and theory must move together. There is a need to tran-
scend data and information, and move to knowledge and action (Berry,
1995). Wisdom is yet another issue. Progressing from information to knowl-
edge is where criminology research can help. Eck (1997) correctly observes
that theory significantly assists in the interpretation of mapped crime pat-
terns.

10.2 Geography and Crime Investigation

From a detective’s point of view, no crime scene is better than a body in a
house ... a body in the street offers less ... Not only are the opportunities
for recovering physical evidence fewer, but the spatial relationship between
the killer, the victim and the scene is obscured ... [But] even a body in an
alley leaves a detective with questions: What was the dead man doing in
that alley? Where did he come from? Who was he with? 

– Simon, 1991, pp. 76–78

One of the focuses of any police investigation is the crime scene and its
evidentiary contents. What is often overlooked, however, is a geographic
perspective on the actions preceding the offence, the spatial behaviour that
led up to the crime scene. For any violent crime to occur there must have
been an intersection of victim and offender in both time and place (Felson,
1998). How did this happen? What were the antecedents? What do the spatial
elements of the crime tell us about the offender’s actions and hunting pat-
terns?

While police officers intuitively know the influence of place on crime,

they are often unaware of the different ways in which geography can assist
their work, of how looking beyond the crime scene tape provides additional
clues (see Dettlinger & Prugh, 1983; Herbert, 1994). In spite of this general
lack of utilization, there are some examples of the application of geographic
principles in the effort to investigate crime and apprehend offenders.

Senior Superintendent Arvind Verma describes how the Indian Police

Service in the Bihar province use geographical analysis in the investigation
of certain kinds of offences (Rossmo, 1995c). Dacoities are a form of violent
robbery dating back to 500 BC, involving gangs of five or more offenders.
As these crimes customarily occur in the countryside, the lack of rural ano-

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nymity requires the dacoity gang to attack villages other than their own, and
then only during those nights when the moon is new. There is usually little
or no artificial lighting in rural India, and the lunar dark phase is a period
of almost complete blackness that provides cover for criminal activities.

Upon being notified of a dacoity, police first determine the length of time

between the occurrence of the crime and first light. Knowing the average
speed that a person can travel cross-country on foot allows them to calculate
a distance radius, centred on the crime site, that determines a circle within
which the home village of the dacoity members most probably lies. There
are few vehicles and if the criminals are not home by daylight, they run the
risk of being observed by farmers who begin to work the fields at dawn.

Those villages of the same caste as the victim village within this circle

are eliminated, as “brother” is not likely to harm “brother.” If a sufficiently
detailed description of the criminals has been obtained, dress, M.O., and
other details can help determine the caste of the gang, allowing police to
further concentrate on the most likely villages. Patrols then speed to intercept
the dacoity members or investigate known offenders residing within the area.

Police dog handlers have noted patterns in the escape routes and move-

ments of offenders fleeing from crime scenes (Eden, 1985, 1994). This pre-
dictability in the behaviour of those under stress has been observed in both
actual trackings of suspects and in experimental reenactments using police
dog quarries. Fleeing offenders tend to turn to the left if they are right handed,
move to the right upon encountering obstacles, discard evidentiary items to
their right, and stay near the outside walls when hiding in large buildings
(Eden, 1985). Different patterns are found when conducting passive tracks
for missing persons. Lost subjects tend to bear to the right in their wander-
ings, and men seem to favour downhill paths while women and children
choose uphill routes (Eden, 1985).

A study of bank robbery escape patterns in the Federal Republic of

Germany, conducted by the national police science research institute of the

Bundeskriminalamt

 (BKA), produced several findings with implications for

police response strategies (Büchler & Leineweber, 1991; see also Leineweber
& Büchler, 1991). The research determined that most offenders (84.8%) plan
their escapes, routes, and vehicle use. Professional criminals also assess bank
location, distance from nearest police station, escape possibilities, and close-
by hiding places. Bank robbers keep to this plan whenever possible, even if
problems develop (which they often do).

Approximately 71% of the offenders are successful in their escape, most

employing a two-stage flight process by switching vehicles or transportation
modes between phases. The first stage generally lasts under 5 minutes, ter-
minating within 2 kilometres of the bank in urban areas, and within 5
kilometres in rural areas. During this stage robbers typically flee on foot

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(41.3%) or by car (44.4%). Escape during the second phase is most often by
vehicle or, less commonly, on foot or by public transportation. Offenders
with accomplices tend to use stolen cars, stay together, and eschew foot
escapes. Robbers stay nearby if they commit a crime in an urban area, and
try to get as far away as possible in a rural area. Overall, 20% of criminals
remain in the vicinity of the bank. The most common destination is a resi-
dence, usually the home of the offender.

The typical police response in Germany to bank robbery is the formation

of a 

Ringalarmfahndung

, a circular blockade. This is an immediate and precise

deployment of police personnel in an effort to apprehend the offenders by
circumscribing the target area. The operation involves both dynamic (patrol)
and static (control point) tactics. The study determined that it took an
average of 26.7 minutes to form a blockade, a length of time that undoubtedly
contributed to its low success rate (15 to 20%).

The BKA research recommended several improvements in the opera-

tional response to bank robbery. It was suggested that circular blockades be
established no greater than 5 kilometres from urban crime scenes. Police
search maps must be simple, accessible, and easy to use. Response time would
be improved through tactical management at the local level, and police
personnel, particularly in supervisory positions, should receive regular train-
ing in blockade formation. Finally, the importance of search information
updates and enhanced interregional communication needs to be recognized.

Police investigations have also been helped through mapping and its

ability to display geographic patterns. During a 1996 murder in Lowell,
Massachusetts, police used a map to show how a trail of the victim’s property,
beer cans, and other physical evidence followed the offender’s likely escape
route, graphically linking the stabbing scene with the murderer’s apartment
residence (Cook, 1998). And after the St. Petersburg Police Department
arrested the suspects in a gruesome 1997 mutilation drug killing, detectives
conducted a unique geographic analysis for the Florida murder trial (Moland,
1998). They tracked the offenders’ mobile telephone usage and associated
cellular antennae sites in the Tampa Bay area, and correlated these locations
with those where victim body parts and other items of physical evidence were
recovered. The resulting map provided compelling evidence for the jury and
both suspects were found guilty.

When the McLean County Sheriff ’s Office in Illinois asked the Mid-States

Organized Crime Information Center (MOCIC) for assistance in the 1995
investigation of a series of almost 60 farm building burglaries, a geographic
analysis revealed two interesting map patterns (Wood, 1998). First, most of
the offences were situated close to a highway, leading to the theory the
offenders were part of a travelling criminal group. Second, the crimes clus-
tered around small rural cemeteries, suggesting the burglars might be using

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them as look-out positions to case targets. These ideas were confirmed and
police were able to prevent any further crimes.

Former police officer Chet Dettlinger observed a geographic pattern in

the Atlanta Child Murders (Dettlinger & Prugh, 1983; see also “Investigators
believe many killers,” 1981). For each victim Dettlinger mapped home
address, place last seen, and body dump site. He noted these locations clus-
tered along 12 major streets in Atlanta that were connected in a boot-shaped
configuration. Questioning the value of such a map, police denied the exist-
ence of any geographic pattern. But in the midst of one of these clusters lay
Penelope Road — the home of Wayne Williams, later arrested for the mur-
ders.

During 1977, in an effort to focus the Hillside Stranglers investigation,

the Los Angeles Police Department (LAPD) tried to determine the most likely
location of the scene of the homicides. It was correctly suspected that the
victims had been murdered in the residence of one of the offenders. The
police knew where the women were abducted, where their bodies were
dumped, and the distances between (Gates & Shah, 1992). The LAPD com-
puter analysts viewed the problem in terms of a Venn diagram, with the
centre of each circle representing victim availability, the circumference rep-
resenting offender movement capacity, and the radius representing offender
mobility (C. Holt, personal communication, February 22, 1993).

Vectors drawn from the point where the victims were abducted to the

location where their bodies were found were resolved to a common radius,
which defined a circle encompassing an area of just over 3 square miles. The
LAPD saturated this “sphere of concern” with 200 police officers in an attempt
to find the murderers. While they were not successful, it is possible that the
heavy police presence inhibited the killers, and prompted serial murderer
Kenneth Bianchi’s move from Los Angeles to Bellingham, Washington. The
LAPD later realized the centre of this zone was close to co-killer Angelo
Buono’s automobile upholstery shop (Gates & Shah, 1992).

Geographic techniques were also used in the Yorkshire Ripper investiga-

tion. With the murders still unsolved after five and a half years, Her Majesty’s
Inspector of Constabulary Lawrence Byford implemented a case review pro-
cess (Kind, 1987a). An Advisory Group, comprised of senior police officers
and a Home Office forensic scientist, met in December 1980 to examine the
investigation (Doney, 1990; Kind). Detectives had become divided over the
issue of where the killer lived. One school of thought, led by the chief inves-
tigating officer, held the Ripper was from the Sunderland area, while other
investigators believed he was local to West Yorkshire where most of the crimes
had occurred (Nicholson, 1979). After an intensive investigative review the
Byford advisory team came to the latter conclusion.