  We search for an evidence of eta-mesic 4He with the WASA-at-COSY detector.
Two dedicated experiments were performed at the Cooler Synchrotron
COSY-Juelich. The experimental method is based on the measurement of the
excitation functions for the two reaction channels: dd-->3Heppi- and
dd-->3Henpi0, where the outgoing N-pi pairs originate from the conversion of
the eta meson on a nucleon inside the He nucleus. In this contribution, the
experimental method is shortly described and preliminary excitation functions
from the 2010 data are presented.
