Italian authorities have unveiled a stolen artwork by the British artist Banksy that was painted as a tribute to the victims of the 2015 terrorist attacks at the Bataclan music hall in Paris.

The L’Aquila prosecutors office said the work by the mysterious artist was recovered on Wednesday during a search of a home in Tortoreto, a city near the Adriatic coast in the Abruzzo region’s Teramo province.

It had been “hidden well” in the attic, prosecutors said in statement on Thursday.

Authorities said they were still investigating how the artwork arrived in Italy and the role of the Italians involved.

They said the discovery was the fruit of a joint Italian-French police investigation.

French officials last year announced the theft of the piece, a black image appearing to depict a person mourning that was painted on one of the Bataclan’s emergency exit doors.

Ninety people were killed at the Bataclan on November 13, 2015, when Islamic extremists invaded the music hall, one of several targets that night in which a total of 130 people died.