A serial rapist on the island of Funen has so far attacked two girls. DNA samples from the attacks confirm it is the same perpetrator, but despite testing several men, the suspect remains on the loose.

While police continue to hunt for the man, opposition party Dansk Folkeparti (DF) argues that he could have been caught a long time ago if there were a comprehensive nationwide DNA database.

“If the police had a nationwide DNA database, the likelihood of finding a match would be greater,” DF’s Peter Skaarup told Berlingske newspaper. “The database would lead to far more crimes being solved quickly. It would also lead to more serial criminals getting caught before they can commit additional crimes.”

The idea of establishing a comprehensive DNA database is not new. In 2003, DF aired the same proposal. Despite being roundly criticised at the time, DF’s revival of the database arrives at a time when DNA technology is becoming increasingly sophisticated and popular as a crime-fighting tool.

Last year’s conviction of Marcel Lychau Hansen – the ‘Amager Attacker’ – for a 1990 murder and six rapes over the past 25 years was largely due to DNA evidence. And recently, police forces across the country announced that they were reopening decades-old ‘cold cases’ in the hope that DNA evidence gathered at the time could produce new suspects.

Ethical dilemma

But while a comprehensive DNA database could reveal the identity of dangerous criminals, it also raises some complicated ethical questions. So much so that the government’s independent ethics commission, Det Etiske Råd, could not arrive at a consensus in 2006 when it was asked to investigate whether Denmark should introduce a comprehensive DNA database that covers all residents.

Danish police already have a DNA database containing the profiles of over 81,000 individuals. According to a 2005 law, only individuals charged or convicted of crimes that carry 18-month minimum sentences or those charged with possessing child pornography have their DNA profiles stored.

While all 17 members of Det Etiske Råd – who are appointed by the government on three-year terms – thought it was not feasible to force all Danes to join a nationwide DNA database, they were split on whether to establish a voluntary database. Many who opposed it argued that the voluntary database should be limited to those convicted of crimes. Other members argued, on the other hand, that it should accept samples from anyone charged with a crime.

But while DNA evidence has been used to find criminals, traditional police methods already produce a high crime clearance rate when it comes to violent crime.

“The database would have most effect in areas of policing that don’t have many resources, such as burglary, where there is a much lower crime clearance rate,” said PhD student Ask Risom Bøge, from the Department of Aesthetics and Communication at Aarhus University.

He added that the major issue with a comprehensive DNA database is the amount of manpower it would take to run because linking a DNA sample to a suspect is not straightforward. Samples often provide links to several DNA profiles in the database – these are known as ‘hits’. But only once the hit has been confirmed by a forensic scientist can a ‘match’ be said to be made.

“The DNA samples quickly deteriorate if they are not stored properly, and samples taken from crime scenes can often contain multiple DNA profiles. This can be a real mess of information that needs to be analysed. This means that you can end up getting many hits on potential suspects who have nothing to do with the crime,” Bøge said, adding that as the size of the database increases, so too does the number of hits the forensic scientists have to analyse.

“So the comprehensive database would require a lot of police manpower to handle the profiles, and also a lot of time investigating which of the hits are actually realistic suspects.”

As a result, Bøge argues that limiting the number of people in the database is the best way to ensure that it remains an effective crime-fighting tool.

“A good database is one that contains the profiles of the active criminal population, where the noise is more limited and a hit is a hit on a person that is already known to police.”

Value for money

Given that only a small amount of crime is solved using DNA, and that the drain on police resources would be huge nationwide, Skaarup’s wish for a comprehensive database looks impractical.

But DNA testing is not the only crime-fighting technology whose benefits do not necessarily justify the cost. For example, last year the police chose not to increase CCTV surveillance after a trial of 40 cameras on the walking street Strøget had no preventative effect.

Surveillance expert Peter Lauritsen from the University of Aarhus said that the return on investment of police CCTV is low.

“Once you start to use it, you face problems with where you place the cameras. And because crime is dynamic and moves around, once you start installing cameras, you have to keep on installing them in new places in order to keep up with the crime,”
Lauritsen said.

Lauritsen added, however, that CCTV footage poses less risk to privacy than a DNA database would. CCTV surveillance gathers so much footage that there are simply not enough people to sit down and watch it all. A DNA sample, on the other hand, contains a vast amount of information about the individual, and it could be used for far more than simply the solving of a crime.

According to Jacob Mchangama, the director of legal affairs for the liberal think-tank CEPOS, this could be a potential risk of a nationwide DNA database.

“On paper, it looks attractive from a crime prevention point of view because it makes it easier to solve crimes and would make people think twice about committing crimes if their DNA was available,” Mchangama said. “But the idea is also frightening, as some politicians have proposed taking the DNA of all newborns and foreigners. The fear is that once the data has been gathered, its use won’t be limited to criminal investigations. It will inevitably spread.”

Trusting Danes

Not everyone is concerned about the infringement on privacy associated with allowing the government to store DNA profiles of innocent people or filming them shopping on a Sunday. A study last year carried out by the domestic intelligence agency, PET, showed that the vast majority of Danes supported surveillance.

“In Denmark, people are positive about surveillance and want more because they trust the state,” Lauritsen said. “We think authorities will use the information meaningfully and positively. Maybe we’re naïve about surveillance, and we need to be more critical, but right now most Danes think it’s great and want much more of it.”

Indeed, while the UK’s expensive failure to introduce a national ID card system failed due to concerns over privacy, Denmark is one of the few European countries with a centralised social security database, the CPR system, in which residents are legally required to file an address. 

It seems that, at least in Denmark, concerns over privacy are unlikely to affect the debate about the creation of a nationwide DNA database. The arguments will instead have to rest on finding an acceptable balance between the crime-fighting benefits of the DNA database and its costs and efficiency.