first of all, plots in Diabolik books are insanely complicated, to the point that I stopped reading balloons and captions from decades
in this case the criminal couple Diabolik and Eva Kant is taking part in a bank heist disguised as members of the gang, but in the meanwhile the bodies of the replaced criminals have been discovered in the mud , and the Police, once alerted, shows up to spoil the fun
Eva is commenting "
chissà come hanno fatto a scoprirci" ( "who knows how they found us" )