The Ha line profile in moustaches is characterized by enhanced wings and a deep central absorption. We explore the possibility that such a profile may be clue to the effect of energetic particles bombarding the atmosphere. Computations show that the characteristics of moustache line profiles can be qualitatively reproduced in two extreme cases, either injection from the corona of high energy particles (60keV electrons or 3MeV protons) or injection in a low-lying site, in middle cthromosphere or deeper, of less energetic particles (～20keV electrons or～400keV protons). The requirements on the energy and on the depth of the injection site of energetic particles are reduced in the case of observations close to the solar limb. The rSle of protons of energies below 1MeV is slightly less ignificant than that of deka-keV electrons in the case of a high particle injection site, but such protons remain to be viable candidates in the case of lower particle injection sites and of observations at larger heliocentric angles. Observations at various wavelengths are needed to find which of these hypotheses is convenient for explaining a given event.