Are quarks and leptons are fundamental particles, or composed of smaller constituents? This question can be addressed at the Large Hadron Collider, CERN, Switzerland using the ATLAS experiment. A search is conducted for deviations from Standard Model expectation in invariant mass and, for the first time, also the angular distribution, in dielectron and dimuon final states.The latest results are presented, using the full LHC 2012 proton-proton collision dataset recorded by the ATLAS detector, corresponding to 20 fb-1 at √s = 8 TeV.