We report on the magnetic behavior of the oxygen deficient LaFeAsO 1− x (x~ 0.10) compound, prepared by one-step synthesis, which crystallizes in the tetragonal (SG P4/nmm) structure at room temperature. Resistivity measurements show a strong anomaly near 150 K, which is ascribed to the spin density wave instability. On the other hand, dc magnetization data show paramagnetic-like features down to 5 K, with an effective moment of 0.83 µ B/Fe. 57 Fe Mössbauer studies (MS) have been performed at 95 and 200 K. The spectra at both temperatures are composed of two sub-spectra. At 200 K the major one (88%) is almost a singlet, and corresponds to those Fe nuclei which have two oxygen ions in their close vicinity. The minor one, with a large quadrupole splitting, corresponds to Fe nuclei which have vacancies in their immediate neighborhood. The spectrum at 95 K exhibits a broadened magnetic split major …