We develop an effective and methodical algorithm for the construction
of general covariant four-point $H\ell\ell Z$ vertices, accommodating
leptons $\ell=e, \mu$, and designed to handle a boson $H$ of
any integer spin, not merely confined to spins up to 2. While our
numerical analysis assumes the $H$-boson mass to be
$m_H=125\,{\rm GeV}$, the analytical framework we propose is versatile,
enabling the examination of various mass as well as spin scenarios.
These meticulously devised general covariant four-point $H\ell\ell Z$
vertices are pivotal in vetoing all the imposters of the Standard Model
Higgs boson holding the spin-0 and even-parity quantum numbers,
especially in one of its primary decay channels, the three-body decay
process $H\to \ell^-\ell^+ Z$, observable at the Large Hadron Collider.
Our innovative strategy encompasses the analysis of all the effectively
allowed scenarios, extending beyond the limitations of previous
investigations on the Higgs spin and parity determinations in the decay
$H \to \ell^-\ell^+ Z$. Based on the significantly expanded
scheme, we demonstrate that the Higgs boson imposter of any spin and parity
can be definitively vetoed by leveraging angular and
invariant mass distributions focusing on threshold effects.
Even though achieving such conclusive results
in practical and exhaustive analyses may necessitate high event rates,
especially in the spin-0 contact-interaction case.