Catherine Hickley has a story in the New York Times outlining yet another restitution case involving the city of Krefeld and its museum which owns four Mondrians from a group of eight that have little documentation surrounding their arrival at the museum around 1930:

The researchers for the heirs, who are known as the McManus Holtzman Irrevocable Trust, tracked the paintings to an exhibition in Frankfurt in 1929. The exhibition was called “The Chair,” and 19 Mondrians, including the four now held by the museum, were offered for sale and displayed above metal tubular chairs, according to [Monika] Tatzkow’s research. A curator planning a show at the Krefeld museum the same year then inquired as to whether some of the Mondrians could be lent to its own exhibition, according to correspondence Ms. Tatzkow found. The heirs believe at least eight Mondrians were lent to Krefeld as a result

The show never came off and Mondrian eventually fled Europe in 1938 to New York where he died and left his works to Harry Holtzman who had arranged his passage to America.

Mondrian’s Heirs Stake Claim to Four Paintings in a German Museum – (The New York Times)