  The problem of vectorial mesons embedded in an electromagnetic field via
Duffin-Kemmer-Petiau (DKP) formalism is reinvestigated. Considering the
electromagnetic interaction as a minimal coupling, an incorrect value $(g=1)$
is identified for the gyromagnetic factor ($g$-factor). Furthermore, it is
shown that is cumbersome to find analytical solutions due to the presence of
the so-called anomalous term for the spin-1 sector of the DKP theory.
Suspecting that the anomalous term results from an incomplete version of the
DKP equation to describe the electromagnetic interaction, we consider the
addition of a non-minimal coupling. This leads to the correct $g$-factor
$(g=2)$, and as a consequence, the anomalous term becomes proportional to an
external four current. As an application, the DKP equation with a static
uniform magnetic field is considered, yielding the corresponding Landau levels.
