Anne Frank died a month earlier than previously believed, according to new research.

Researchers from the Anne Frank House in Amsterdam looking into the last months of the teenage diarist and her sister Margot concluded that they died in February 1945, according to a statement from the Anne Frank House. The statement was published on March 30, the 70th anniversary of the official date of the sisters’ deaths set by Dutch authorities after the war.

The researchers used the archives of the Red Cross, the International Tracing Service in Bad Arolsen and the Bergen-Belsen Memorial, in addition to as many eyewitness testimonies of survivors as possible, the statement said.

The exact date of Anne Frank’s death from typhus in Bergen-Belsen concentration camp is unknown. — jta