Schleyer 's abduction was planned by Siegfried Haag .
Schleyer was arrested in 1976 , so Schleyer 's replacement , Brigitte Mohnhaupt , carried out the abduction .
Schleyer 's abduction was planned by Siegfried Haag , but he was arrested in 1976 , so his replacement , Brigitte Mohnhaupt , carried out the abduction .