It's Dutch alright. Flemish really is no different language.
1st page:
Fanny (daughter): You are a mean bastard!
Marcel Kiekeboe (father): Spot on.
Blonde crook (he appears to be a francophone): Ca suffit (enough)! It's alright! Ellen, go get Sofie out of the backyard! While we tie them up!
Bl. Crook: To the garage! Vite (quick)!
Br. Crook: Originally it was meant to get rid of you father.
Br. Crook: But you kept getting in my way, and as such...
Charlotte (mother): What do we get now? She's returning with a goat!
Bl. Crook: Dédé le Canaille n'est pas contraire (Dédé the crook isn't that cruel). I'm not such a bad person. And for this I have planned a more pleasant end.
Br. Crook: For dying of laughter about (makes no sense in English lol).
Dédé: We start with the girl! La fille!
Br. Crook: Hey! It doesn't work!
Fanny: I'm currently not in the mood for laughing!
Charlotte: We don't have to depend on the police. We have to do something ourselves!
Konstantinopel (son): I have an idea!
2nd page:
Konstantinopel: Do you see that piece of wood. Listen...
Dédé: Untie her! I have something else pour elle.
Dédé: We'll see how monsieur reacts to Sofie!
Marcel: Hahahaha. Stop it!
Br. Crook: Dad seems to have a great laugh! (dunno how I can translate lachebekje, it means "laughing mouth")
DOOIIING!
Dédé: The bell. Parblue! Who can this be?
Dédé: Sam, go watch! Et toi, stop laughing!
Marcel: Hahaha!... Sorry! ... I can't stop... Hahahaha!
Sam: Snap! It's Konstantinopel!
Sam: Over here you!
Konstantinopel: He's arriving!
Sam: Stay here!
Charlotte: You mean lay here!
TONK!