  Ibohal, Ishwarchandra and Singh proposed a class of exact, non-vacuum and
conformally flat solutions of Einstein's equations whose stress tensor $T_{ab}$
has negative pressure. We show that $T_{ab}$ corresponds to an anisotropic
fluid and the equation of state parameter seems not to be $\omega = -1/2$. We
consider the authors' constant cannot be the mass of a test particle but is
related to a Rindler acceleration of a spherical distribution of uniformly
accelerating observers.
