  We present and briefly discuss results of several studies of the source
J2102+6015 with tentatively defined redshift z=4:575 which demonstrates unusual
properties in imaging and astrometric VLBI observations. Its properties might
be considered as indications on the supermassive black hole binary which can be
considered as a so far rare example of a high-redshift source of known
electromagnetic and, possibly, predictable gravitational wave emissions.
