The family of James Foley has released a letter written by the journalist before his death, revealing intimate details of his detention at the hands of the Islamic State.

The letter, posted on the ‘Free James Foley’ Facebook page, was memorised by a fellow hostage just before they were released.

• Secret US bid to rescue James Foley failed
• UK rapper prime suspect in US journo execution

The 40-year-old used the letter to pay tribute to his family, saying that he was proud of his brothers and sisters.

“It makes me happy to think of them. If there is any money left in my bank account, I want it to go to Michael and Matthew,” Foley said of his younger brothers.

Foley also said that he planned to take his grandmother out when he got home.

“Grammy, please take your medicine, take walks and keep dancing. I plan to take you out to Margarita’s when I get home. Stay strong because I am going to need your help to reclaim my life.”

All other letters written by Foley were confiscated by his captors, his family said.

The American journalist’s final letter went into great detail about the conditions of his detention.

“Eighteen of us have been held together in one cell, which has helped me. We have had each other to have endless long conversations about movies, trivia, sports,” Foley wrote.

“I have had weak and strong days… We try to encourage each other and share strength. We are being fed better now and daily. We have tea, occasional coffee.”

Foley was beheaded by his jihadist captors last week after efforts by the American government to rescue him failed.

It was later revealed that his captors demanded a $100 million EURO ransom for his release.

It is unclear who Foley’s 17 cellmates were, but six French and Spanish journalists held captive were released by the Islamic State in April.