Two-pion decay modes of the N*(1440) in n p -> d pi pi

A simple model for the n p -> d pi pi reaction has been developed. It is shown that the deuteron momentum spectra measured at T_n = 795 MeV can be understood in terms of the Roper excitation and its N pi pi decay modes. A similar pattern, recently observed in p p -> p p pi+ pi-, can be explained in the same way.