Napoli wanted to be absolutely certain Antonio Conte was not involved in their clash with Juventus on Saturday.
There's reports Napoli staff requested an investigation into the Juventus stadium, to be sure there were no 'secret tunnels' for Conte to use.
Conte has been suspended all season due to the betting scandal, so must watch games from the stands even though he can train the side regularly during the week.
Conte is visible during the match behind a Plexiglas screen in the VIP box at the Juventus Stadium, but Napoli insisted on checks to ensure there were no 'secret tunnels' allowing him to access the locker room at half-time.