The office of Manhattan District Attorney Alvin Bragg has seized three drawings by Austrian artist Egon Schiele that investigators say were stolen from their owner, Jewish collector and cabaret performer Fritz Grünbaum, by the Nazis during World War II. 

Bragg’s team, the New York Times reports, issued warrants to three out-of-state museums that owned the works: the Art Institute of Chicago, for Schiele’s Russian War Prisoner (1916); the Carnegie Museums of Pittsburgh, for Portrait of a Man (1917); and the Allen Memorial Art Museum at Oberlin College, for Girl With Black Hair (1911). The warrants, which Artnet News reviewed, allow for the institutions to hold onto the artworks for now.

Valued between $1 million and $1.5 million each, the two watercolors and a pencil drawing are among roughly a dozen Schiele artworks that Grünbaum’s heirs are attempting to recover through a series of ongoing civil lawsuits. Plaintiffs in the cases are David Fraenkel and Timothy Reif, both co-trustees of Grünbaum’s estate, and Milos Vavra. 

The descendants, who say that the Nazis forced Grünbaum into signing an unlawful power of attorney in 1938, while he was detained at Germany’s Dachau concentration camp, previously recovered two Schiele watercolors—Woman in a Black Pinafore (1911) and Woman Hiding Her Face (1912)—from London-based art dealer Richard Nagy. (The artworks were sold in November at Christie’s for $500,000 and $2.5 million, respectively.) 

The heirs have also filed lawsuits against the Morgan Library and Museum, the Museum of Modern Art, and the Santa Barbara Museum of Art. 

The Manhattan D.A.’s got involved in the current claims because the Schiele pieces were, at some point, trafficked through New York. Charges have not been filed against the museums.  

Bragg’s office declined to comment, citing an “ongoing investigation.” 

“Carnegie Museums of Pittsburgh is deeply committed to our mission of preserving the resources of art and science by acting in accordance with ethical, legal, and professional requirements and norms,” the institution said in a statement shared with Artnet News. “We will of course cooperate fully with inquiries from the relevant authorities.” 

“We are confident in our legal acquisition and lawful possession of this work,” a spokesperson for the Art Institute said. “The piece is the subject of civil litigation in federal court, where this dispute is being properly litigated and where we are also defending our legal ownership.” 

The Allen Museum did not respond to a request for comment by press time.  

Grünbaum amassed an impressive collection of Austrian art, including some 80 pieces by Schiele, during his lifetime. He was killed at Dachau in 1941.