  We use a recent formalism of the weak hadronic reactions $\tau^- \to
\nu_{\tau} M_1 M_2$ to study the helicity amplitudes in $\tau^- \to \nu_{\tau}
V P$ decay. This recent formalism maps the transition matrix elements at the
quark level into hadronic matrix elements, and finally writes the weak matrix
elements in terms of easy analytical formulas evaluated by means of an
elaborate angular momentum algebra. The formalism provides directly the
amplitudes for the different spin third components of the vector mesons
involved. We extend the formalism to a general case, with the operator
$\gamma^\mu -\alpha\gamma^\mu \gamma_5$, that can account for different models
beyond the standard model and study in detail the $\tau^- \to \nu_{\tau} K^{*0}
K^{-} $ reaction for the different helicities of the $K^{*0}$. The results are
shown in terms of the $\alpha$ parameter that differs for each model. We find
that $\frac{d \Gamma}{d M_{\rm inv}^{(K^{*0} K^{-} )}}$ is very different for
the different components $M=\pm 1, 0$ and in particular the magnitude $\frac{d
\Gamma}{d M_{\rm inv}^{(K^{*0} K^{-} )}}|_{M=+1} -\frac{d \Gamma}{d M_{\rm
inv}^{(K^{*0} K^{-} )}}|_{M=-1} $ is very sensitive to the $\alpha$ parameter,
which makes the investigation of this magnitude a most welcome initiative to
test different models beyond the standard model.
