Forget the dirty old man in a grubby raincoat thumbing through a dog-eared girlie magazine.
By Kim Griggs
In Wellington, New Zealand
These days it is likely to be internet-savvy young men, living at home with their parents who are trading illegal pornography, says a report.
Pornographic images are traded via the web
The New Zealand study, the final version of which is due to be released at the end of the month, provides an insight into the type of person downloading illegal porn and violent images.
"Most commentary on the internet revolves around this idea that young people could be seduced by a person and taken away and horrible things could be done to them," says Angela Carr, the report's leading author.
"The fact is that young people could be the horrible pervy internet people," Ms Carr told BBC News Online.
In 1996, New Zealand established the Censorship Compliance Unit. These specialists are part of New Zealand's Department of Internal Affairs.
They enforce New Zealand's censorship legislation, which deems illegal the possession or trade in such material as sexual images of children and young people, images of torture, bestiality and necrophilia.
Now the purveyors of illegal pornography have moved into the virtual world, so too has this unit that hunts them down.
The study profiled 106 people who have been investigated by the Censorship Compliance Unit. The bulk of the people profiled in the Department of Internal Affairs study were identified via the internet.
In the study, the offenders were overwhelmingly male (only one was a woman), mostly Caucasian, likely to be middle class and adept at using the internet.
Virtually all of the offenders (99) had collected child pornography. But other types of material were collected as well. Seventeen had images of sexual violence, 27 had scat images, 32 bestiality, and 14 had images of torture. Two had images of necrophilia.
The offenders' ages, at the time they were investigated, ranged from 14 to 67 with the average age being 30.
But almost a quarter of the offenders were aged less than 20 years.
Almost a third of the offenders were students and a third lived at home with their parents or grandparents. The most common age of offending in the study's sample was 17.
The secondary school students in the study tended to be a sexually curious group, often living out of town, with few local alternatives for sexual exploration.
"What is worrying is that their internet-based exploration has led them to subject matter involving largely deviant activities at a time when they are most likely to be influenced by the message it conveys," the study says.
Students studying for degrees were most likely to be city dwellers but were also likely to be loners.
"An apparent lack of other social interaction suggests that social isolation may also be a factor in the development of their interest in objectionable material," the study suggests.
Younger censorship offenders tended to be treated more leniently, the study points out.
"Inspectors and judicators frequently treat offences committed by young people as less serious than those committed by adults.
"Clearly, the literature also shows that most adolescent sexual offenders do not persist beyond adolescence, however, some do," the study says.
Apprehending offenders in the virtual realm is easier than detecting a physical offence, says Angela Carr.
"It's easier to prove that they were trading in objectionable material than it is that they offended against a three-year-old," she says.
"So if we can pick them up in this medium, we can get them early or at least get them, and try and provide some sort of treatment or intervention," she says.
Any intervention for younger offenders should be tailored for their age, suggests Ms Carr.
"Putting them into the criminal justice system may do more harm than good in terms of stigmatising and labelling them and bringing them into increased contact with other offenders."
After the 33 students identified in the study, the next biggest group was the information technology industry and white collar/administrative positions.
"These individuals may have a higher likelihood of internet involvement purely because the technology is more familiar to them, and a greater part of their lives, than for the general population," says the study.
"However, the fact that no women were identified in the sample ... suggests that this factor is also insufficient in terms of explaining offending," the study says.
The department cautions against using the findings of the study to make a causal link between viewing child pornography and offending against children, but does say its findings suggest an association between the two.
Even though the majority of offenders in the study did not have a criminal history, the number of those who had committed sexual offences was greater than in the general population.
And offenders' interest in their 'subjects' was often more than voyeuristic.
Some of the offenders had access to young children, either though their work or though voluntary activities such as soccer coaching and babysitting.
Study suggests link between viewing child porn and offending
Similar links also occurred where offenders were interested in other types of objectionable images. One offender, who possessed necrophilic images, was professionally involved with funeral directors.
Another, who had images of bestiality, worked with animals.
The diversity of the offenders would make it a mistake to merely swap one stereotype for another, says Angela Carr, formerly with Internal Affairs but now employed as a university researcher in Australia.
But she also says there needs to be social recognition that young people may not only be at risk from the internet but could be offending online.
"People don't tend to suspect young people of doing this. You get a young, attractive, virile 25-year-old man. Nobody's going to look at them and suspect them," says Ms Carr.