Theta1 Orionis A: An exciting triple system in the heart of the Orion Trapezium Cluster Authors: M. Petr-Gotzens and M. Massi (ESO, Garching and MPIfR, Bonn) More than a decade ago, strong non-thermal variable radio-emission had been detected from theta^1 Orionis~A, the third most luminous OB star in the Orion Trapezium Cluster. The source of the emission, has been a puzzling issue since then. As theta^1 Orionis~A, is a close triple stellar system, it has also been difficult to identify which component of the system actually is the radio emitter. In this talk a re-analysis of available VLBI radio data combined with adaptive optics near-infrared observations is presented and a scenario for the enigmatic radio emission is suggested.