The primary goal of the Kepler mission is the measurement of the frequency of Earth-like planets around Sun-like stars. Transit timing variations (TTVs) may offer the possibility for these confirmations of near-resonant multiple systems by the mutual gravitational interaction of the planets. We previously detected the second planet candidate in the KOI 1574 system. The two candidates have relatively long periods and are in 5:3 resonance. We therefore searched for TTVs in this particularly promising system. We detected strong anti-correlated TTVs of the 114 d and 191 d signals, dynamically confirming them as members of the same system. Finally, we also detected two more short-period super-Earth sized planetary candidates in the system, making the relatively high multiplicity of this system notable against the general paucity of multiple systems in the presence of giant planets like Kepler-87 b.