Triplet states of the CO molecule in the region between 86 000 and 94 000 cm-1 have been investigated in a 1 + 1 double-resonance experiment using a detection scheme based on laser-reduced fluorescence (LRF). The strongly predissociated (3pσ) j 3Σ+ Rydberg state at 90 833 cm-1 with an average lifetime of 4.6 ps has been observed spectroscopically at high resolution for the first time, providing a clear identification of this state. Both the accidental predissociation of the J f=6 level of CO (E 1Π, v = 0) and the value of the lambda-doubling constant q of the c 3Π state can be attributed to j 3Σ+. In addition, a valence state around 91 960 cm-1 has been identified as 3Π. Accurate molecular constants have been determined for both states.