  A simple protocol for complete and deterministic Bell state measurement is
proposed. It consists of measurements of nonlocal spin product operators with
the help of shared entanglement as an ancillary resource. The protocol realizes
not only nonlocal Bell state measurement between a pair of distant qubits but
also a complete Bell filter that transmits either one of the Bell states
indicated by the measurement outcome. These schemes will be useful in quantum
technologies where nonlocal Bell state measurement is indispensable.
