  Gamma ray burst sources are isotropically distributed. They could be located
at distances $\sim 1000$ AU. (Katz \cite{JK92}) GRB signals have many narrow
peaks that are unresolved at the millisecond time resolution of existing
observations. \cite{JK87} CETI could use stars as gravitational lenses for
interstellar gamma ray laser beam communication. Much better time resolution of
GRB signals could rule out (or confirm?) the speculative hypothesis that GRB =
CETI.
