The strain glassy phase is produced by doping a small percentage of impurity in a martensitic alloy. Its ground state is conceived to consist of martensitic nanodomains spatially separated from each other by a defect phase. The present study, by probing the local structure around the Ni and Ti in martensitic and strain glassy compositions of ${\mathrm{Ni}}_{50+x}{\mathrm{Ti}}_{50\ensuremath{-}x}$, identifies the defect phase that is responsible for inhibiting the long range ordering of the elastic strain vector leading to the formation of the strain glassy phase.