A spokesman for Porsche confirmed reports in German weekly magazines Spiegel and Focus over the weekend that the baby monitor was found in Wiedeking's hotel room last November, although it is not clear whether his security team found it before or after he had spent the night there.
Porsche is trying to take over VW, but is being blocked by the state government of Lower Saxony which holds a decisive share of the company and wants to retain its influence.
The struggle between Porsche and Lower Saxony goes to the heart of German business philosophy, pitting Porsche's purely capitalist intentions against the idea of keeping public involvement in a national company.
Neither magazine offered any indication to who might have planted the baby monitor in Wiedeking's room – or whether it would have worked well enough to listen in to any conversations he had there. A VW spokesman said the company had nothing to do with any bugging attempt.
The baby monitor was initially thought to have been left in the room by a family, but the hotel said no families had stayed there, so the authorities were called in and an investigation has been launched.
Although the idea of using a baby monitor which would deliver only poor quality sound might seem ridiculous, there have already been a number of bugging incidents at VW and Porsche, the magazines say.
Focus reports that the offices of Porsche workers' organization head Uwe Hück are to be made bug proof after it was discovered that his phone was being tapped. And Der Spiegel says that a bug was found planted in the private flat of former VW chief Wolfgang Bernhard.