  We present an analysis of the plasma parameters during the initial phase of
the 12 June 2010 flare (SOL2010-06-12T00:57). A peculiarity of the flare was
the detection of $\gamma$--emission that is unusual for such weak and short
event. The analysis revealed the presence of a flare precursor detected about 5
minutes before the flare onset in 94 \AA \ images which spatially coincided
with the non-polarized microwave (MW) source at 17 GHz (\textit{the Nobeyama
Radio Heliograph}) that is the Neutral Line associated Source (NLS). A
comparison of the results obtained from MW data by \textit{the Nobeyama Radio
Polarimeters} and \textit{the multi-frequency Siberian radioheliograph} (the
new 10-antenna radio heliograph prototype at 4.6 and 6.4 GHz) and hard X-ray
(HXR) observations by \textit{the Fermi Gamma-ray Space Telescope} reveal the
presence of accelerated electrons during the flare initial phase. The analysis
of MW and HXR spectra also confirms the presence of accelerated particles.
Moreover a good temporal correlation between several lightcurves in different
HXR energy bands and at MW frequencies indicates generation of both HXR and MW
emission by a common population of accelerated electrons. Detection of
accelerated particles during the initial phase of the flare and
soft-hard-harder (SHH) behavior of the spectra indicate several episodes of
particle acceleration and confirm the non-impulsive type of the flare
evolution.
