oil in spark plug on 2006 Saab 9-7x

problem is oil is getting into one spark plug but no one has a clue from where

Asked by for the 2006 Saab 9-7x
Need to clarify this.
The oil gets to the spark plugs externally, around the porcelain insulator and connection, or gets into the combustion chamber and build up a deposit at the electrodes?

1 more answer
This is possibly oil leaking from the coil assembly in the Direct Ignition Cassette.