Infiltrating a swarm of artificial or living agents using a single monitoring robot could allow for the assessment of their swarm rules and parameters without the need for any external infrastructure. The inferred swarm model could then be used to control these swarms, for example to guide them to safe areas. In this study we introduce a scheme for autonomous artificial agents to extract knowledge about the interactions within a swarm of interest. By infiltrating the swarm of interest with a monitoring robot and constantly measuring the distance between the infiltrator and its nearest neighbour, the repulsion radius of the swarm agents can be estimated. Though this method works for a range of tested parameters, it is still limited to a specific model of interaction.