  The eta-mesic nuclei in which the eta meson is bound with nucleus via strong
interaction was postulated about 25 years ago, however till now no experiment
confirmed empirically its existence. The discovery of this new kind of an
exotic nuclear matter would be very important for better understanding of the
eta meson structure and its interaction with nucleons. The search for eta-mesic
helium is carried out with high statistic and high acceptance with the
WASA-at-COSY detection setup and the Cooler Synchrotron COSY. The search is
conducted via the measurement of the excitation function for the chosen decay
channels of the 4He-eta system. Until now two reactions dd -> (4He-eta)bound
->3Heppi- and dd -> (4He-eta)bound ->3Henpi0 have been measured with the beam
momentum varied continuously around the eta meson production threshold. This
contribution includes description of recently published results of the
WASA-at-COSY experiment as well as brief presentation of preliminary results
from the analysis of new data sample with 20 times larger statistics.
