  In this paper we pursue the study of linear perturbations around a
Schwarzschild black hole in a generalized Einstein-Cartan theory of gravity,
called torsion bigravity. This theory contains both massless and massive spin-2
excitations. Here we consider non spherically-symmetric perturbations with
generic multipolarity $L \geq 1$. We extend the conclusion of linear stability,
previously obtained for $L=0$ [Phys. Rev. D 104, 024032], to the generic $L
\geq 1$ case. We prove that the mass $\kappa$ of the massive spin-2 excitation
must be large enough, namely $\kappa r_h > \sqrt{1+\eta}$, to avoid the
presence of singularities in the perturbation equations. The perturbation
equations are shown to have a triangular structure, where massive spin-2
excitations satisfy decoupled equations, while the Einstein-like massless
spin-2 ones satisfy inhomogeneous equations sourced by the massive spin-2
sector. We study quasi-bound states, and exhibit some explicit complex
quasi-bound frequencies. We briefly discuss the issue of superradiance
instabilities.
