The double murder in Danish Herlev in June last year was filmed by a witness. When the registration number was reported, the Danish police searched an extensive road camera system to map out how the getaway car moved in Denmark through the car's registration number.

It also helped police identify a second car, a Fiat Punto, used by the suspects. Within a few days, the main suspect was arrested, in Aarhus, and in the next few weeks, the remaining four co-defendants were arrested in Stockholm. Two of them were 17 years old when the murders took place.

Various crimes

The technology with the cameras is found on Danish police cars and 48 stationary cameras along Danish roads. It was introduced despite criticism that personal data was collected.

The cameras have automatic readings of registration numbers and are used according to the Danish police to fight everything from terrorist crimes and gang crime to drug smuggling and traffic crimes.

It was also used to track the car two Swedes used when they detonated a bomb outside the Tax Agency in Copenhagen in August last year, just weeks after the double murder. Two events that led to Denmark introducing border controls against Sweden.

"Will help us"

Here in Sweden, there are also automatic readers, so-called ANPR cameras, whose abbreviation stands for automatic number plate recognition . The cameras are currently available on 200 police cars.

But Pia Glenvik, project manager for the police's national camera project, would like to see a system similar to the one in Denmark that makes the police connected to the road cameras.

- It will take us forward in our criminal investigations if we get it in Sweden, she says.

As an example, she points out that the system could have been helpful in the case of the murder of the 12-year-old girl in Botkyrka just over two weeks ago. With the camera system, the police had been able to quickly find out how the white getaway car that was used moved after the attack.

- How has this car moved in this area? Has it been there before or since? Then they can search for, perhaps, a white car.