Whodunnit?

The is the motley crew that turned up for the Sorley Ring post grand prix dinner on New Year's Eve.  As is usual at this kind of event, someone died and foul play was involved.  Any ideas whodunnit?

Shiek Djuluvme (Darren), Marsha Ull (Sue), Penelope Bust-Op (Claire), Gracie Nipelle (Rachel), Ivor Bigend (Simon), Max Speed (David), Slik Tyres (Jenny), Minnie Cooper (Diane),