Cesar (Child Exploitation & Sexual Abuse Repository) is a database system for saving photo and video footage that has already been viewed by detectives in investigations into child sexual abuse. The Dutch National Child Abuse Database is one such system.
Much of the illegal footage circulating on the internet and within certain networks emerges again and again in police investigations. And each time, the images are viewed by detectives. With Cesar, this is no longer necessary, so eliminating repeated work.
All of the photos and videos in a case are classified by detectives. This classification information and the image itself is then sent to and saved in a safe database environment. In each new investigation, the seized files are first compared with the data in Cesar, giving insight into which illegal and legal material is already known by the police. There is then no need to view the material again.
There must be no doubt whatsoever of the quality of the Cesar database. Each detective needs to be certain that the information in the national database is reliable, which is why Cesar includes meticulous quality control, and the police force itself selects the criteria it wants to apply. The Dutch police have, for instance, established that a photo is only added to the national database when it has been placed three times in the same category by different detectives.
Cesar is an effective tool in the fight against child sexual abuse and is frequently used in tactical investigations. The database is continually updated so that all the police forces have constant access to the same up-to-date information. This information is then used to expose ties vital to the investigation.
‘The Dutch police lead in tracking down child sexual abuse thanks to the national database’
‘The national database is a result of collaboration between the Dutch police and ZiuZ. An online connection links the database to our teams and new material is analyzed and uploaded to the database throughout the day. The central database is then synchronized overnight, so that everyone has access to the latest information the very next day.’
Fast and efficient
‘We used to work with a different database, but it was never up to date. We once ran an investigation involving 208 suspects – it lasted 18 months. If we’d had the current database, we’d have been able to work through the case much more quickly. And our detectives wouldn’t have had to view the same material again and again.
Tactical investigations
‘The national database is a valuable source of information in tactical investigations. Each image includes information on the date, place and sort of camera used, and we add other relevant information to this about the case itself. This can all be found in the national database, so helping us group information and make specific searches through it.
Punishable and non-punishable material
‘There is a huge volume of digital footage on most of the computers seized, yet only a fraction of this material is actually illegal. We can gain a lot of time by archiving non-punishable material. In fact, sometimes we can rule out half the footage.’
One of a kind
‘A lot of the material is used in court cases, so the national database has to be reliable. In order to guarantee the quality of the classifications, we’ve made sure an image only gets added to the database after three detectives have independently analyzed the image and indicated that it is illegal material. It’s a fully automated process and the only one of its kind in the world.
Dave Jansen, Reinforcement Program against Child Abuse Material
Dutch national police
