Rolla was a Melcene and a member of Brador's secret police (i.e., Bureau of Internal Affairs). He was described as having a large, bulbous nose. He was surprised to run into Silk and Garion in Melcena and revealed that Zakath was very unhappy that Garion and his party ran off from him in Mal Zeth.
Garion did not want Silk to assassinate Rolla to cover their tracks.