Geneva public prosecutor Yves Bertossa has opened a corruption investigation into a $100-million payment in 2008 by late Saudi King Abdullah to former King of Spain Juan Carlos I, Bloomberg reported on Sunday.

Bertossa last year convened a closed-door meeting with legal scholars to determine whether or not the payment to Juan Carlos, who has extensive financial holdings in Switzerland, constituted a criminal offense. He requested a closed-door hearing in February to discuss the resulting opinion, which came just a month after Spanish prosecutors announced they would investigate Juan Carlos for possible crimes linked to a high-speed rail contract in Saudi Arabia, won by a Saudi-Spanish consortium. The intense scrutiny, according to Bloomberg, “could roil Switzerland’s longstanding role as a preferred destination for Saudi wealth.”