The last known living 9/11 search dog has died in America aged 16.
A statement from the Texas A&M Engineering Extension Service says Golden Retriever Bretagne was put to sleep on Monday at a veterinary clinic in the Houston suburb of Cypress.
Bretagne (Pronounced: Britney) was two years old when she and her handler, Denise Corliss, took part in the 9/11 search operation in New York.
Almost 3,000 people died in a series of attacks on America in September 2001.
Four planes were hijacked with two crashed into the World Trade Centre towers in Lower Manhattan, New York.
Another plane hit the Pentagon in Virginia and a fourth was forced to ditch in a field near Shanksville, Pennsylvania, by passengers on board.
Bretagne and Denise Corliss were part of the Texas Task Force 1 sent to the World Trade Centre site after the terror attacks on 9/11.
They spent 10 days at the scene searching rubble for human remains.
Nearly 100 other search and rescue dogs were used after 9/11 to try to find and save people trapped in the rubble of the World Trade Centre.
Bretagne retired from active duty aged nine.
After retiring, Bretagne helped other search dogs and volunteered at a reading programme at a primary school in Texas.
Aged 15, Bretagne was taken by Denise Corliss to the 9/11 memorial.
While she was in New York last year, she was treated to a suite at 1 Hotel Central Park and took a taxi ride through Times Square.
She was also a 2014 finalist for the American Humane Association's annual Hero Dog Awards.
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