Magnetic fields are amplified as a consequence of galaxy formation and large-scale dynamos driven by a turbulent cascade. Galaxy mergers can potentially enhance and amplify the magnetic fields from their progenitors, making the fields dynamically important, but the role of mergers on magnetic fields is still poorly understood. We use thermal polarized emission observations with HAWC+/SOFIA to trace the magnetic fields in the molecular gas of the nearest radio active galaxy, Centaurus A, which is thought to be the remnant of a merger. Here, we detect a ~3.0 kpc-scale magnetic field tightly following the molecular warped disk. We find that the small-scale turbulent field become more efficient at high velocity dispersions and column densities in the molecular warped disk. This result has strong implications on understanding the generation and role of magnetic fields in the formation of galaxies across cosmic time.