  We give reasons for the existence of the NN decoupled dibaryon resonance
$d^*_1$(1956). Strong evidence for its presence has first been found in the
energy spectrum of coincident photons emitted at $\pm 90^0$ from the $pp \to
\gamma\gamma X$ process at 216 MeV measured by the DIB2$\gamma$ collaboration
at JINR. As further experimental indications of the $d^*_1$(1956) existence we
present those found in the available photon energy spectra of $np\gamma$,
$pd\gamma$, and $pA\gamma$ reactions below the pion threshold. It is noted that
serious discrepancies between the $np\gamma$ and $pd\gamma$ experimental cross
sections and theoretical calculations can reasonably be explained by the fact
that latter did not take into account the $d^*_1$ effect.
