The alpha-decay of a low energy isomer of Th-229 at about 3.5 eV was sought by producing it through the (gamma,n) reaction on a Th-230 target. Thorium isotopes in the reaction products were isolated and purified by anion exchange chromatography in a concentrated nitric acid medium to remove lanthanides fission products. The thorium fraction was further purified by samarium fluoride coprecipitation and the precipitate was mounted as a source for alpha-spectroscopy. Decaying alpha-signals were observed in the energy region that was expected for (229)mTh, i.e., between 4.83 and 5.08 MeV. The half-life of the decaying component was determined from repeated experiments to be 13.9+/-3 hours.