Relations between the clubs have soured since Soriano and director of football Txiki Beguiristain left the Nou Camp and it could all be set to come to a head over the impending transfer of Brazilian superstar Neymar.
Barca president Sandro Rosell is believed to have tied up an agreement with the player to join his club from Santos at some point in the future, originally expected to be after the World Cup in 2014.
That deal may now be brought forward to this summer after City attempted to lure him to Manchester instead with claims that Soriano and Beguiristain spoke to members of the striker's family when Brazil played England at Wembley earlier this month.
Rosell was angered by that and reports today that Soriano, who was an ally of former Barca president Joan Laporta, has been investigated by the Catalan authorities over email spying are being interpreted as an attempt to discredit him by a rival powerbroker.
City declined to discuss the prosecutor's findings, which state Soriano ordered cyber intelligence company Cybex Experience to embed a device in the server of the club's internal computer, enabling all internal emails containing any one of 100 keywords to be monitored.
There has also been a number of reports claiming that Soriano has gone back on an "honourable" pledge not to take players from Barcelona, by trying to sign Cesc Fabregas, Sergio Busquets and Pedro Rodriguez - which they have not.