Helge Achenbach, Germany’s top art adviser, is behind bars. That is, for now, at least. Further details have emerged about the extent of the alleged fraud committed by Achenbach against Bertold Albrecht, the heir to supermarket giant, Aldi. A 24-page complaint filed by Albrecht’s widow, Babette Albrecht, alleges that Achenbach defrauded the billionaire couple of at least €18 million, according to Germany’s Handelsblatt.

According to reports, the alleged fraud was committed by altering and falsifying purchase invoices for art works and vintage automobiles. Achenbach is alleged to have increased the prices of those invoices or changed the currency of the price from dollars to euros, according to the Rheinische Post (RP). The latter method alone would have secured the art advisor a 30-40 percent increase in the price, considering recent exchange rates. On top of these, reports note that a higher sales price would have also increased his  commission for arranging the sales and the VAT charged to the client.

As artnet News previously reported, Achenbach is currently held under what is called Untersuchungs-Haft, a pretrial investigatory detention phase typically enforced when authorities consider an accused individual a flight risk or fear that the individual might manage to cover up alleged crimes before an investigation is complete. The 62-year-old adviser was arrested on June 10th, following his return from Brazil where he had been installing a project, Campo Bahia, in the German World Cup team’s eponymous training camp.

According to Thomas Elsner, who represents Achenbach’s family and spoke with the RP, the situation is rather more complex than it has thus far been made out to be. In his statement, Elsner suggests that many of the agreements made between Bertold Albrecht and Helge Achenbach were verbal and thus may not reflect documents which Babette Albrecht allegedly possesses. Elsner also suggests that the deceased didn’t wish to involve his wife in many of his dealings with Achenbach. He says flatly that no manipulation or alteration of invoices took place.

Unsurprisingly, a spokesperson for Babette Albrecht said Achenbach absolutely did falsify the documents. And, according to the Handelsblatt, if that is true, Albrecht may not have been his only mark. The paper reported on Wednesday that Christian Boehringer, scion to the Boehringer pharmaceutical dynasty, may have also been duped by Achenbach’s alleged practices. The Handelsblatt reports that Boehringer was defrauded of €1.2 million over the course of his dealings with Achenbach, funds which have since been returned without legal intervention. The Essen prosecutor’s office had previously reported that there was a second potential claimant against Achenbach. It is unclear if this is Boehringer. The paper suggests that Boehringer is just a witness at this time.