In an experiment involving detection of a photoelectron and up to three photoions from C O2 in coincidence, we observe the triple ion coincidence C+: O+: O+. Moreover, we observe double coincidences between doubly charged cations and singly charged cation pairs C2+: O+, O2+: C+, O2+: O+. These ion triplets and pairs arise from fragmentation of the triply charged molecular ion C O2 3+. Other ion pairs-viz., C+: O+, O+: O+, O+: C O+ -arising from the doubly charged molecular ion C O2 2+, are also observed. From an analysis of the coincidence pattern we postulate four decay modes of the C O2 3+ ion. Kinetic energy release in the channel leading to C+: O+: O+ is measured, and its distribution is postulated to have four contributing precursor states. © 2006 The American Physical Society.