Let K be a field of characteristic p > 0, let G be a locally finite gr
oup, and let K[G] denote the group algebra of G over K. In this paper
we study the Jacobson radical JK[G] when G has a finite subnormal seri
es with factors which are either p'-groups, infinite simple, or genera
ted by locally subnormal subgroups. For example, we show that if such
a group G has no finite locally subnormal subgroup of order divisible
by p, then JK[G] = 0. The argument here is a mixture of group ring and
group theoretic techniques and requires that we deal more generally w
ith twisted group algebras. Furthermore, the proof ultimately depends
upon certain consequences of the classification of the finite simple g
roups. In particular, we use J.I. Hall's classification of the locally
finite finitary simple groups.