Anna Nicole Smith was investigated by the FBI over an alleged plot to kill the son of her late oil tycoon husband during a bitter court battle over his estate.
The late Playboy Playmate married 89 year old multi-millionaire Howard Marshall II in 1994, when she was just 26.
Following his death from natural causes in 1995, Smith claimed she had received a verbal promise from her husband that she would receive half of his estimated $550 million (£366 million) fortune.
The tycoon's son, E. Pierce Marshall, launched legal action to try and prevent the star getting her hands on any of the money, arguing that various wills and trusts his father had prepared over the years named him sole heir.
Now, newly obtained FBI documents - released through America's Freedom of Information act - reveal that Smith was interrogated by agents between 2000 and 2001 over a reported plot to hire a hitman to kill Pierce Marshall.
A reporting agent who compiled the case notes writes, "Smith adamantly denied ever contemplating such a crime," adding that "Smith began crying and denied ever making such plans" when she was questioned.
The investigation was subsequently dropped after an assistant U.S. attorney, Sally Meloch, reviewed the reports and "determined that there is insufficient evidence to establish that there was a murder-for-hire plot by Ms. Smith to kill Pierce Marshall."
It is not known where information of the alleged plot was obtained, but the report adds a revolver, a steel knife, and a black and orange hat were all removed from Smith's home. They were returned seven months later.
Pierce Marshall died of an infection in 2006, aged 67. A year later (07) Smith died at a hotel in Florida.
The battle to gain access to Marshall's fortune is still being fought by the late star's estate. If won, the money will go to Smith's three year old daughter, Dannielynn.