Did someone fall down the stairs or were they pushed? NFI and TU Delft are working on a model for complex falls

Imagine: a dead person is lying at the foot of the stairs in a house. Did the person fall, was he or she pushed, or killed earlier and placed there to make it look like an accident? These are often extremely complex cases for investigators and can get bogged down or approached incorrectly. To change this, researchers Arjo Loeve and Winfred Mugge from TU Delft are working with the Netherlands Forensic Institute (NFI) on a computer model that can simulate human falls. In the future, the model must support police and the Public Prosecution Service (OM) in finding the most likely scenario of what happened.

How someone is positioned at the bottom of the stairs can often give the police an initial idea of what may have happened. Is the person lying in a conspicuous position, for example? Investigators at the scene will then try to interpret what may have happened and match the evidence to a scenario. ‘But sometimes what you can see at first glance is somewhat different from what actually happened,’ says forensic scientist and project leader Jan Peter van Zandwijk. ‘That is why a computer model could help investigations.’

Simulation model

That is why the NFI launched the Icarus project two years ago. The researchers decided on a commercial computer model developed for the automotive industry. Van Zandwijk and a TU Delft student, Kim Hutchinson, have been testing that model for the past two years with the aim of discovering whether it can be used for forensic investigation. ‘It’s similar to a “crash test dummy”, which is a doll they use to simulate car crashes,’ Hutchinson explains. ‘Our model is just a virtual dummy, a human model in a computer. Based on the laws of physics, it calculates how the human model falls when you put it in a certain position or push against it with a certain force.’ It is possible to give the doll different starting positions, simulate a fall and then watch where it lands. Therefore, the researchers can use the computer model to simulate a fall or a movement in which someone has been pushed, for example.