Portrait of a Young Girl by Dutch artist Toon Kelder, displayed in the home of Dutch SS collaborator Hendrik Seyffardt's descendants. (Photo credit: Screenshot/X/@brand_arthur)

A Nazi-looted artwork has turned up in the residence of a Dutch SS collaborator's relatives, according to details from The Guardian about an art detective's probe.

The painting, Portrait of a Young Girl by Dutch artist Toon Kelder, formed part of the collection owned by Jewish art dealer Jacques Goudstikker prior to its seizure by Nazis invading the Netherlands.

The Guardian reports that the piece had adorned the wall in Hendrik Seyffardt's family home for decades, a case art detective Arthur Brand calls the strangest of his career.

Brand was contacted by a man who recently learned of his connection to Seyffardt, a top Dutch Nazi sympathizer in World War II.

This individual disclosed that the stolen painting had long been displayed in the hallway of Seyffardt's granddaughter's house.

The granddaughter admitted to the relative that the artwork was looted but claimed it could not be sold and urged silence, per Brand.

Speaking to Dutch outlet De Telegraaf, the man expressed shame over his family's possession of the painting and insisted it belongs with Goudstikker's heirs, prompting his outreach to Brand.

De Telegraaf notes that Seyffardt's descendants had mulled returning the work upon discovering its illicit origins.

"My mother gave it to me. Now that you mention it this way, I see why Goudstikker's heirs would want it back. I had no idea," one relative told De Telegraaf.

Art detective probes origins of stolen painting

The Guardian recounts how Brand initiated a thorough investigation. He found a Goudstikker label on the canvas and the number 92 etched into the frame. Digging into records from a 1940 auction of plundered Goudstikker pieces, he confirmed Portrait of a Young Girl as lot number 92.

Brand determined Seyffardt acquired the painting at that sale and bequeathed it to his kin.

Goudstikker family attorneys verified the theft and demanded repatriation, according to The Guardian.

On Monday, Brand posted on X/Twitter that Seyffardt's relatives surrendered the painting to him and a reporter.