  We perform 3+1 general relativistic simulations of rotating core collapse in
the context of the collapsar model for long gamma-ray bursts. We employ a
realistic progenitor, rotation based on results of stellar evolution
calculations, and a simplified equation of state. Our simulations track
self-consistently collapse, bounce, the postbounce phase, black hole formation,
and the subsequent early hyperaccretion phase. We extract gravitational waves
from the spacetime curvature and identify a unique gravitational wave signature
associated with the early phase of collapsar formation.
