Complex sentence: Giafranco Tizzoni, a Mafia supergrass, identified Grassby as being at the "beck and call" of the Calabrian Mafia for at least 40 years and according to the National Crime Authority the Mafia funded Grassby's election campaigns.
Split into simpler sentences: Giafranco Tizzoni, a Mafia supergrass, identified Grassby as being at the "beck and call" of the Calabrian Mafia for at least 40 years. According to the National Crime Authority, the Mafia funded Grassby's election campaigns.