Originally Published: 27 FEB 23 11:58 ET

Updated: 27 FEB 23 12:02 ET

Nadeen Ebrahim, CNN

(CNN) -- The sale of an Egyptian presidential passport at an auction is causing anger and confusion.

The family of the late Egyptian President Anwar Sadat has called on authorities to investigate the sale of the leader's passport at a US auction house, arguing that the travel document is part of the nation's heritage.

Sadat's diplomatic passport was sold on February 22 for $47,500 by Dallas, Texas-based Heritage Auctions, according to its website.

Karim Sadat, the president's grandson who is also a member of parliament, said that selling his grandfather's passport is "an insult that we, as a family and as representatives of the Egyptian people who love the late president, will not accept," reported the state-owned Ahram newspaper.

The lawmaker told an Egyptian TV talk show host on Saturday that he expects the foreign ministry to investigate the incident.

Many have wondered how the passport made its way to the auction house.

Sadat said that, as far as he knows, the president's wife handed her husband's belongings to the Library of Alexandria in northern Egypt after he died. But Ahmed Zayed, the library's director, told the same talk show host on Saturday that the passport was not among the belongings.

Details of the passport's new owner were not disclosed on the auction page.

Issued March 19, 1974, the travel document has forty-eight pages and is unsigned, according to Heritage Auctions. It was valid until March 18, 1981 and has one stamped visa from 1974.

Heritage Auctions did not respond to CNN's request for comment.

A former Egyptian army officer, Anwar Sadat was president from 1970 until his assassination in October 1981. For many Egyptians, Sadat is a symbol of their country's fight for independence. He led Egypt through the 1973 Arab-Israeli war, but later made peace with Israel by signing the US-brokered Camp David Accords in 1978. Sadat's foreign diplomatic efforts were acknowledged when he shared the 1978 Nobel Prize for Peace with Israeli Prime Minister Menachem Begin.