Be spin-spin relaxation time, T2, has been observed in (U,Th) Be13 compounds. In contrast to CeCu2Si2, a decrease of T2 with decreasing temperature is observed below T, If the temperature dependence of T2 is truly an intrinsic property of (U,Th) Be13, a new interaction should be introduced to interpret this anomalous behavior of spin-spin relaxation in these compounds.