Authorities in Argentina have detained the daughter and son-in-law of Friedrich Kadgien, a financial advisor to Adolf Hitler. This comes after the disappearance of a 17th-century painting suspected of being Nazi loot from a coastal property in the Argentinian city of Mar del Plata, according to The Times of Israel.

The disputed artwork, believed to be ‘Portrait of a Lady’ by Italian baroque painter Giuseppe Ghislandi (1655–1743), surfaced in a house listing earlier this year. Dutch newspaper AD spotted the painting in photographs of the property, which once belonged to Kadgien, who fled to Argentina after the Second World War and died there in 1978. Shortly after the story was published, the painting disappeared.

Prosecutors said on Sept. 2 that Kadgien’s daughter and her husband were placed under house arrest for three days. They are expected to face charges over the painting’s disappearance.

The family, however, claims the piece belongs to them. Their lawyer, Carlos Murias, told local newspaper La Capital that they were willing to cooperate with investigators. Argentine daily La Nacion also reported that the couple insisted they had inherited the artwork legitimately. Despite these assurances, prosecutors confirmed to The Times of Israel that the painting has not been handed over.

Interpol and Argentina’s federal police are involved in the case, which has gained international attention due to its ties to looted paintings from the Nazi era. Four property searches conducted earlier this week failed to locate the missing Ghislandi art work, although investigators seized two other 19th-century artworks from the home of another Kadgien daughter. Officials noted that “the works will be analysed to determine if they are linked to paintings stolen during World War II.”