Associated Press - October 7, 2009 5:24 AM ET
MIAMI (AP) - Files obtained exclusively by The Associated Press say the FBI investigated whether Anna Nicole Smith was part of a plot to kill her tycoon husband's son, whom she was battling for his late dad's fortune.
The FBI files say prosecutors ultimately decided there wasn't enough evidence to charge the model and Playboy Playmate who died of a drug overdose in 2007.
Smith was investigated in 2000 and 2001 in the alleged plot targeting E. Pierce Marshall. At the time, he was fighting Smith to keep her from collecting his late father's vast oil fortune. The younger Marshall has since died.
No evidence of Smith's alleged involvement in such a plot is detailed, but she was questioned.
An FBI agent says she cried and denied any involvement.