We have found a long-lived metastable state of stopped-pi- in liquid helium by measuring the time spectra of two different delayed products: (i) protons emitted after pi--absorption by He-4 nuclei and (ii) 70-MeV electrons originating from free pi- --> e--nu(e)BAR decay. The lifetime and fraction of delayed pi--absorption obtained by using the emitted protons are 7.26 +/- 0.12 nsec and 1.66 +/- 0.05%, respectively. The free-decay fraction of a pion in liquid helium was obtained to be 0.64 +/- 0.03% from this result, which is consistent with the observed free-pi- decay fraction. These results imply that 2.30 +/- 0.07% of stopped-pi-are trapped in the metastable state which have an overall lifetime of 10.1 +/- 0.2 nsec. The same experimental and analysis were performed for stopped-pi- in liquid neon, where no evidence for trapping was found.