We report 13C NMR measurements on the spin-1/2 triangular-lattice antiferromagnet κ-(ET)2Cu 2(CN)3 without any magnetic transition down to 30 mK. The 13C NMR spin-lattice relaxation becomes inhomogeneous, following a stretched exponential below 4 K down to 20 mK, This relaxation profile, and a gradual broadening of the spectra, suggest that spatially inhomogeneous moments of small amplitude emerge at low temperatures under magnetic fields. © 2006 American Institute of Physics.