A quasar model is presented in which the accretion disk around the black hole is constantly replenished by matter from stars near the nucleus of a galaxy, as the stars are captured by the accretion disk and are destroyed inside it. The model solves the problem of how the large mass of a black hole was carried to the very small nuclear region of a galaxy from which the quasar light is emitted, and implies a relation between the mass of the black hole and the central velocity dispersion of the stars that matches the observed M-sigma relation.