There were reports about Holleeder having talks with a few NLS-connected criminals. A hit like this - albeit a botched one - doesn't sound too far off in that case. Though usually the NLS seem to be a bit more thorough in their hits than what happened here.
They arrested three suspects. Even if it has nothing to do with Holleeder, it will have an effect on Astrid and her sister. Those spy shops do business with a lot of crooks.
