  The recent LIGO event GW170817 is the merger of a double neutron star system
with an associated short GRB170817A with $2.9\pm0.3$\,s soft emission over
8-70\,keV. This association has a Gaussian equivalent level of confidence of
5.1$\sigma$. The merger produced a hyper-massive neutron star of stellar mass
black hole with prompt or continuous energy output powering GRB170817A. {Here,
we report on a possible detection of} Extended Emission (EE) in gravitational
radiation {\em during} GRB170817A: a descending chirp with characteristic time
scale $\tau_s=3.01\pm0.2\,$s in a (H1,L1)-spectrogram up to 700\,Hz with
{Gaussian equivalent level of confidence greater than 3.3$\sigma$ based on
causality alone following edge detection applied to (H1,L1)-spectrograms merged
by frequency coincidences. Additional confidence derives from the strength of
this EE.} The observed frequencies below 1kHz indicate a hyper-massive magnetar
rather than a black hole, spinning down by magnetic winds and interactions with
dynamical mass ejecta.
