A rich trove of works and photographs by the artists Alberto Giacometti has been seized from a Swiss museum. The works have been held under lock and key for the past two years owing to a legal dispute concerning their rightful ownership.

The seizure of the collection by Swiss prosecutors comes ahead of a decision by a French court after the Alberto and Annette Giacometti Foundation alleged the works were stolen decades earlier. The identity of the accused remains unknown but the disputed collection includes 16 Giacometti sketches as well as 101 photographs of him made by Robert Doisneau, Henri Cartier-Bresson, and Man Ray.

Giacometti can lay claim to being one of the best known sculptors of the 20th century and in 2015 his sculpture, Pointing Man, sold at Christie’s for $141 million—the highest sum ever paid for a sculpture.

Art historians have shown immense interest in the collection as it is believed the photographs give an intimate glimpse into Giacometti and his contemporaries. One photo by the late Cartier-Bresson shows Giacometti and his wife descending a staircase to enter his studio in Paris.