In Peril at End House, Bert Croft is an Australian renting the lodge close to End House with his wife. He and his wife are not what they seem, and are caught up in the murder mystery when they try and run a scheme of their own.
Mr Croft is about sixty years old, and at least six feet tall. He has "a powerful frame and a weather-beaten face". He has vivid blue eyes, and is almost completely bald.
Mr Croft often comes up to End House to give Nick Buckley vegetables that he has grown in his garden at the lodge. Nick describes him as "oppressively kind", and she finds him rather a nuisance.
Some time before the events of the novel, Nick went for surgery for appendicitis, and Mr Croft asked her if she had made a will. She made one there and then, and Mr Croft offered to post it to her lawyer, Charles Vyse.
It is later revealed that Mr and Mrs Croft were forgers. There had been an accident to the car they had made their last getaway in, and Mrs Croft had sustained a spinal injury, causing them to have to rent the lodge at End House, while she recovered. It is further revealed that they had forged a will, stating that Nick left everything she had to Mrs Croft. Mr Croft had then posted the forged will, and not Nick's actual will, to Charles Vyse.