Several models of physics beyond the Standard Model predict neutral particles that decay into final states consisting of collimated jets of light leptons and hadrons (so-called "lepton jets"). These particles can also be long-lived with decay length comparable to, or even larger than, the LHC detectors' linear dimensions. This talk presents the results of the search for lepton jets in proton--proton collisions at the centre-of-mass energy of s√ = 8 TeV in a sample of 20.3 fb−1 collected during 2012 with the ATLAS detector at the LHC. Perspectives and new ideas for Run2 will be discussed as well.