  Theoretical ab initio studies of resonances in the unbound ${\rm^{7}He}$
nucleus are presented. We perform no-core shell model calculations with $NN$
interactions Daejeon16 and JISP16 and utilize the SS-HORSE method to calculate
the $S$ matrix for two-body channels $n{-}{\rm^{6}He}$ and
$n{-}{\rm^{6}He^{*}}$ with ${\rm^{6}He}$ respectively in the ground and excited
$2^{+}$ states as well as for the four-body democratic decay channel
${{\rm^{4}He}+n+n+n}$. The resonant energies and widths areobtained by
numerical location of the $S$-matrix poles. We describe all experimentally
known ${\rm^{7}He}$ resonances and suggest an interpretation of an observed
wide resonance of unknown spin-parity.
