U.S. singer and social activist Harry Belafonte has filed a lawsuit against the estate of Martin Luther King Jr. over an ownership dispute of documents that Belafonte said were given to him by the late civil rights leader and his wife, according to court documents filed on Tuesday (October 15).

Belafonte claims ownership of three documents associated with King and his widow, Coretta Scott King, which is being disputed by King's estate and daughter, Bernice King, the lawsuit filed in U.S. District Court in New York.

The documents in dispute are an outline of the "Casualties of the War in Vietnam" speech that Belafonte said he has had since 1967, the "Memphis Speech" that was undelivered, found in one of King's suit pockets after his death, and a condolence letter from President Lyndon Johnson sent to King's widow after his assassination in 1968.

King's estate and daughter Bernice King disputed Belafonte's ownership of the documents when the singer took the items to Sotheby's auction house in New York to be appraised and put up for sale in 2008, the lawsuit said.

The items were withdrawn from auction after King's estate and daughter said Belafonte had "wrongfully acquired" them, according to court documents.

Belafonte, 86, known as the "King of Calypso" with his Caribbean musical influences, has long been an advocate for civil rights and was a close friend and supporter of King.

The singer is asking the court to declare that the documents belong to him, that they were not taken from King and to bar King's estate and daughter permanently from trying to claim ownership of the items.

Presented by Adam Justice