Oct. 7, 2009 -- Before she died in 2007, Anna Nicole Smith was investigated by the FBI in connection with an alleged murder plot against the son of her late oil tycoon husband, but the former Playboy Playmate was never prosecuted.
According to documents obtained by The Associated Press, the FBI investigated Smith in 2000 and 2001 in a murder-for-hire plot targeting E. Pierce Marshall. Marshall fought to keep Smith from inheriting his father J. Howard Marshall's multi-million dollar estate after he died in 1995, less than a year after marrying Smith.
The case bounced around the courts for years until the Supreme Court unanimously ruled in May 2006 that Smith could pursue her late husband's fortune. The younger Marshall died a month later from an infection. Smith died the following year, in February 2007, from a drug overdose.
Federal agents interviewed Smith on July 3, 2000. When she was told why she was being questioned, the report said, "Smith began crying and denied ever making such plans."
After reviewing the reports, prosecutors determined there was insufficient evidence for the case to go forward.
As part of the probe, the FBI confiscated a .357 Smith and Wesson revolver, a 3 1/2-inch stainless-steel knife and, for unexplained reasons, a black and orange hat described as "Dr. Seuss." All three objects were returned to her about seven months later.
Smith was 26 when she wed the 89-year-old J. Howard Marshall. According to an interview with the younger Marshall, included in the FBI report, Marshall said Smith rarely spent time with his father and that his father complained that she asked for $50,000 to $60,000 twice a week.
Since Smith's death, her lawyer and companion Howard K. Stern and two doctors, Dr. Sandeep Kapoor and Dr. Khristine Eroshevich, have been charged in California with helping the model obtain drugs that ultimately killed her. All have pleaded not guilty.
ABC recently obtained affidavits showing that Smith's doctors had crossed boundaries to indulge in "unprofessional" relationships with their patient.
The documents submitted to a Los Angeles judge in support of search warrants in the case suggest that Smith's psychiatrist Khristine Eroshevich and internist Sandeep Kapoor had relationships "that appeared sexual in nature" with the model, who was found dead in a Florida hotel room.
The medical examiner determined that 39-year-old Smith died after an accidental drug overdose involving nine different medications or an "acute combined drug intoxication."
According to the affidavits, photographs were discovered in the investigation depicting Smith naked with Eroschevich in a bathtub in "intimate embraces" that "constitute unprofessional behavior."
Asked about any sexual relationship with Smith, Eroschevich's attorney Aadam Braun said, "Anna was a dear friend of Dr. Eroshevich. Dr. Eroshevich would never have done anything to hurt her friend."
"Dr. Eroshevich tried her best to help her friend and patient Anna get through a very difficult period following the loss of a child," said Braun. "Although the care might not have been perfect it was consistently guided by Dr. Eroshevich's desire to help Anna cope with this horrific lost and the psychiatric and other medical issues exacerbated by it."
A video, originally aired on "Inside Edition," is also mentioned in the affidavit and is described as showing Kapoor shirtless in a "reclining position" with Smith at a nightclub.
"His arm was around Smith and he was 'kissing and nuzzling Smith's neck,' reads the affidavit.
Ellyn Garofalo, the attorney representing Kapoor, called the suggestion of a sexual relationship between her client and Smith "wrong."
"There was no social relationship of any kind, much less a sexual relationship, between Kapoor and Smith," said Garofalo. "It just never happened."
"Dr. Kapoor is openly gay and was at the time and there will be no evidence of any social interaction except that one day at the gay pride parade when they were both there," said Garofalo, referring to a photograph taken of Smith and Kapoor at a nightclub that she says has since become fodder to suggest there was a sexual relationship between the two.
Eroshevich and Kapoor, as well as Smith's boyfriend and attorney Howard K. Klein, helped supply Smith with a lethal cocktail of drugs, the affidavits allege. All three co-defendents pled not guilty to related charges in court in May.
In the affidavit, a Los Angeles pharmacist who was asked to a prescription on behalf of the late former Playboy model referred to the requested concoction as "pharmaceutical suicide" and refused to fill the order.
"Some of the amounts of medications Dr. Kapoor has prescribed would be lethal if the whole amounts were taken in the time period before the next refill of the medication," read the affidavit.
Jon Genens, a senior investigator with the Medical Board of California, wrote in the documents that "in many instances, Dr. Kapoor prescribed more than double the recommended dosage of controlled substances."
These controlled substances included Ambien, Klonopin, Valium, Xanax, Ativan, methadone and Dilaudid. Many of these were prescribed for Smith during her pregnancy, despite the fact that these narcotics could have resulted in a miscarriage or birth defects, according to the affidavit.
It was also found at the time of Smith's death that the model had prescriptions for 44 medications under at least nine aliases, according to the affidavits. Stern's name was also listed as an alias for Smith on medicine bottles, according to the documents.
"The information in that affidavit is wrong," said Garofalo. "They miscalculated results and when you see the medical records, it's our view that Dr. Kapoor acted at all times in good faith."
Garofalo said that Kapoor "didn't know about any other doctors" and "never had any contact with any other doctor [prescribing medication to Smith]."
Stern's attorney, Steve Sadow, declined to comment on his client's case, citing a status hearing scheduled for tomorrow that he'd prefer not to speak in advance of. According to Sadow, the status or motion hearing involved "discovery-related matters and scheduling."
Renee Rose, the Los Angeles prosecutor on the case, declined to comment on the proceedings, saying, "We're going to present our evidence and then let the judge make the determination."
ABC News legal expert Dana Cole, who has followed both the Smith case as well as the ongoing Michael Jackson case, said that the two definitely have some similarities.
"It's interesting that there are two high-profile investigations going on right now in Los Angeles regarding celebrities and prescription drug cases," said Cole. "It shows that a lot of these celebrity doctors have problems saying 'no' to their famous clients."
But Kapoor's attorney said that the public's interest in the prescriptions given to Jackson is likely to only bolster her client's case.
"The Michael Jackson case is going to highlight the differences between Dr. Kapoor and Anna Nicole's treatment and the kind of excessive prescribing that may or may not be appropriately charged as criminal conduct," said Garofalo. "I think this will educate the public."
"The Jackson case is going to show why [Smith's] case should never have been prosecuted criminally," she said. "What Kapoor did was medically sound."