  Within a covariant Bethe-Salpeter approach, the relativistic complex
separable neutron-proton interaction kernel is proposed. The uncoupled
partial-wave states with the total angular momentum $J$=0,1 are considered. The
multirank separable potentials elaborated earlier are real-valued and,
therefore, enable to describe the elastic part (phase shifts, low-energy
parameters, etc.) of the scattering only. The description of the inelasticity
parameter comes out of the imaginary part introduced into them. To obtain
parameters of the complex potentials the elastic neutron-proton scattering
experimental data up to 3 GeV are used. A signal of dybaryon resonances in the
$^3P_0^+$ partial-wave state is discussed.
