Isn't a German cell also suppose to be involved in the OK bombing?
According to Jayna Davis, it was probably an Iraqi Al Qaeda cell with direct ties to Saddam Hussein's regime and intelligence service.
The German link you are referring to may be the German, Andreas Strassmeir, who may have been an German intelligence agent (perhaps ex-Stasi and a double agent), who was helping train the white supremacist gang to which McVeigh was likely aligned.
The ones behind the entire OK City operation were the Iraqis, quite likely in league with Al Qaeda who were using white supremacists McVeigh and Nichols as foot soldiers.
Read all about it in The Third Terrorist
IIRC, the Elohim city guys had ties to some guys in Germany.