The Dzyaloshinskii-Moriya interaction is thought to be responsible for the stabilization of weak ferromagnetism or magnetic spiral states in a number of diverse systems. An interesting manifestation of this effect is the observation of anisotropic weak ferromagnetism spanning a limited temperature range in the brownmillerite Ca2Fe2O5. The anti-symmetric Dzyaloshinskii-Moriya interaction is thought to be responsible for concomitant electric and magnetic orders in many systems, and our preliminary investigations also indicate that Ca2Fe2O5 is a potential multiferroic candidate. To gain more microscopic information on the various exchange interactions in this material, we propose inelastic neutron measurements on single crystals of Ca2FeO5 using the MERLIN instrument.