In the Internet of Mobile Things (IoMT) applications dealing with mobile objects may benefit from information if two or more objects are in co-movement, i.e. if they are close to each other and sharing the same movement pattern during some interval of time. In this demo we demonstrate how co-movement can be reliably monitored in a mobile middleware component executing on a smartphone using Complex Event Processing over streams of accelerometer data generated by SensorTags interacting with the smartphone through Bluetooth Low Energy.