The paper discusses recent perturbed γ-γ angular correlation (PAC) studies [Metzner and collaborators, Phys. Rev. Lett.53, 290 (1984)] of the111In/111Cd decay in Cu that had been damaged by the neutrino recoils associated with the decay of solute111Sn atoms to the PAC mother nuclei111In. It is argued that these experiments may settle a long-standing controversy on radiation damage in metals in favour of the so-called two-interstitial model.