  We present new data for four candidate obscured Compton-Thick (CT) quasars at
z $\sim$1-2.5 observed with SINFONI VLT spectrograph in AO mode. These sources
were selected from a 24$\mu$m Spitzer MIPS survey of the COSMOS field, on the
basis of red mid-infrared-to-optical and optical-to-near-infrared colours, with
the intention of identifying active galactic nuclei (AGNs) in dust enshrouded
environments, where most of the black hole mass is assembled in dust enshrouded
environments. Near infrared spectra were analyzed in order to check for
emission line features and to search for broad components in the
[OIII]-H$\beta$ and H$\alpha$-[NII] regions. X-ray spectral analysis, radio and
MIR diagnostics, and SED fitting have also been employed to study the nature of
the sources. We successfully identified three objects for which we had only a
photometric redshift estimate. Based on their emission line diagnostics and on
ancillary multi-wavelength constraints, we find that all four targets harbor
obscured AGNs. Broad profiles that could be attributed to the effects of
outflows are revealed in only one target, MIRO20581. In particular, we clearly
resolved a fast ($\sim$1600 km/s) and extended ($\sim$5 kpc) outflow in the
[OIII]5007 emission line. This feature, the commonly used indicator for ionised
outflowing gas, was sampled and detected only for this target; hence, we can
not exclude the presence of outflows in the other sources. Overall, the
constraints we obtain from our targets and from other comparative samples from
the literature suggest that these optically faint luminous infrared galaxies,
hosting obscured AGNs, may represent a brief evolutionary phase between the
post-merger starburst and the unobscured QSO phases.
