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Spatial Characteristics of
Serial Sexual Assault in New
Zealand
Dr Samantha Lundrigan
Victoria University of Wellington
Research Aims
 To examine the characteristics of New
Zealand sex offenders with respect to:
 Spatial behaviour
 Consistency in offence environment
selection
The New Zealand Context
 4million in a land
area of 268,680 km
sq.
 92% rural land, 8%
built up.
 2001 population
density of 14 per km
sq.
Data collection
 Police files – New Zealand Police
Criminal Profiling Squad
 Crime scene, background and
geographical information coded and
mapped
The sample
 76 serial offenders
 Between 1970 and 2002
 Collectively 270 offences (mean of 3.5 per
series)
 Characteristics
 70% strangers, 20% friend/associate, 1%
previous partner
 Mean age of 23 (12-60)
 53% NZ Maori, 21% NZ European, 18% Pacific
Island People
Results
Journey to crime
Criminal
Range
50.00
mindist (km)
40.00
30.00
20.00
10.00
0.00
0.00
50.00
100.00
150.00
200.00
maxdist (km)
r = 0.470 (P<.001)
250.00
300.00
Spatial pattern
 Marauders 37%, Commuters 34%, Transients 29%
Measure
Marauders (median
km)
Commuters
(median km)
Mean distance travelled**
2.36
5.78
Min distance travelled*
0.18
0.91
Maximum distance travelled**
4.75
11.73
Mean Interpoint Distance
12.89
4.40
Max distance between offences
20.28
8.73
Min distance between
offences*
01.17
0.32
* p<.05 ** p<.01
Environmental
consistency
 Variables








Type of contact site
Victim transportation
Day of week
Time of day
Distance to offence
Area type
Land use
Deprivation score
Consistency score
 Mean 4.56, Median
4.79, Standard
deviation 1.70
 Min 1, Max 8
Score
N
Cum%
0≤ 2
8
10.5
2≤ 4
24
42.1
4≤ 6
31
82.9
6≤ 8
13
100.0
Consistency score
 44 (57%) of offenders scored above 4,
the score midpoint.
 Proportional chance expected 2.5% of
offenders (z=45.42, p<.0001).
Future Research
 More detailed analysis of environmental
characteristics
 Offender-offence environment
consistency
 Implications for Geographic profiling
systems
Thank you
 Dr Samantha Lundrigan
Institute of Criminology
Victoria University of Wellington
Wellington
New Zealand
[email protected]