Omar, the fourth son of Osama bin Laden, who was known to have openly disagreed with his father's moves, has taken exception to the way his father was killed unarmed and without a trial.

Omar, 30, said he always disagreed with his father over the violent means and had sent numerous messages denouncing them and urging him to “change his ways”. But even the U.S. forces which had killed Osama have violated the international law by killing an unarmed terrorist leader without a trial, he said in statement issued by the Bin Laden family but signed only by him. The statement was the first by the family after Osama's killing.

Omar made it clear that the family did not believe that the Al Qaeda leader was dead. “If the mission was indeed successful,” is how he began the statement.

We are not convinced on the available evidence in the absence of dead body, photographs, and video evidence that our natural father is dead, Omar bin Laden wrote in the statement that was released to the New York Times.

Therefore, with this press statement, we seek such conclusive evidence to believe the stories published in relation to May, 2, 2011 operation Geronimo as declared by the President of United States Barrack Hussein Obama in his speech that he authorized the operation and killing of OBL and later confirmed his death.

Citing the instances of Saddam Hussein and Slobodan Milosevic who were given a fair chance of justice before they were executed, Omar took exception to the way his father was not arrested and tried in a court of law.

Seeking answers to his queries, he said in case of no reply the family will be forced to go to the “International forum for justice -- International Criminal Court, International Court of Justice and UN.”

They “must take notice of the violation of international law and assist us.”

“A panel of eminent British and international lawyers is being constituted and a necessary action may be taken if no answers are furnished within 30 days of this statement,” he ended his statement with a harsh tone.