The rotationally resolved spectrum of the HCBr (A) over tilde(1)A "(0,2,0)<--(X) over tilde(1)A’(0,0,0) K-a = 0<--1 transition between 12760 and 12850 cm-l was obtained for the first time at Doppler-limited resolution using a transient frequency-modulation absorption technique. Rotational structure of HC Br-79 and HC Br-81 was identified and analyzed. The analysis shows R "(C-Br)=1.85(2) Angstrom and R’(C-Br)=1.74(9) Angstrom. The observed band indicates a linear-bent transition. This yields an upper limit of approximately 1600 cm(-1) for the barrier to linearity above the zero-point energy for the (A) over tilde(1)A " state. Perturbations caused by singlet-triplet interactions were also found in the observed spectrum. The analysis of these perturbations indicates a very low-lying (a) over tilde(3)A " state.