We report the results of measurements of 2 7 Al NMR spectra and the DC susceptibility of polycrystalline decagonal quasicrystalline Al 6 9 . 8 Pd 1 2 . 1 Mn 1 8 . 1 . The temperature variation of the magnetic susceptibility χ(T) and the 2 7 Al NMR-spectra imply that a fraction of the order of 20% of the Mn-atoms carry a magnetic moment, and that a spin-glass-type freezing of these Mn moments occurs at T f =12K. The NMR spectra reveal two partially resolved lines for the 2 7 Al nuclei, indicating that there are two different sets of local environments for the Al-sites. Below 100K and upon decreasing temperatures, the 2 7 Al-NMR line width Δ increases with a progressively increasing negative slope dΔ/dT, as it is often observed in relation with spin-glass freezing processes.