An improved 3-local characterization of McL and its automorphism group

This article presents a 3-local characterization of the sporadic simple group McL and its automorphism group. The proof of the theorem is underpinned by two further identification theorems, one due to Camina and Collins and the other proved in this paper. Both these supporting results are proved by using character theoretic methods. The main theorem is applied in our investigation of groups with a large 3-subgroup [11].