The -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 -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 system. Until now two reactions and 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.