A man who claims he tipped federal investigators to the location of Osama bin Laden's compound in Pakistan eight years before his killing and has hired attorneys to help him collect the $25 (£15.6) million reward.
Gem dealer Tom Lee, 63, claims that in 2003 a Pakistani intelligence agent, from a family he had known for decades, told him bin Laden was in Peshawar in Pakistan, not Afghanistan, Fox News reported.
The Al Qaeda leader was killed in May 2011 during a Navy SEAL raid on the three-story compound. U.S. officials have said the house wasn't built until 2005, and Pakistani officials have said they believe he moved there in the summer of that year.
But Lee has allegedly described how he had been sent on a mission by Pakistani intelligence services to relocate bin Laden and his family to a small compound in Bilal, Abbottabad.
A letter obtained by The Associated Press, sent by Mr Lee's lawyers to FBI director James Comey in August, claims Mr Lee shared his information with FBI agents.
But despite "numerous attempts" to claim his reward after bin Laden's death in 2011 he received no response.
"Mr Lee precisely identified the whereabouts of the most notorious terrorist of our era," said the letter.
"A man responsible for the World Trade Center attacks, the most devastating act of terror committed on American soil, and numerous other assaults on Americans."
Mr Lee told The Grand Rapids Press in an email on Friday that he did not understand why the government waited to act for eight years.
"It disturbs me, and it should disturb every American, that I told them exactly where bin Laden was in 2003, and they let him live another eight years," he said in the email.
Mr Lee, who became Lord of Stanbury Manor in England in 1997 after purchasing the title, claims to have provided the FBI with intelligence before, and said the lack of action surprised him.
"For 20 years I was used to the government acting immediately on my intelligence," he said.
During their hunt for bin Laden, US authorities offered the reward to anyone who supplied information that led to bin Laden's capture or conviction.
The FBI has so far refused to comment, Sky News reported.