The daughter of Russian oligarch Boris Berezovsky thought he had been poisoned in the days after he lost a multibillion-pound court battle with football club owner Roman Abramovich, his inquest has heard.
Elizaveta Berezovskaya said her father told her "something strange was happening to him" and said "some chemical reaction was inside him" but they later realised he was suffering from depression.
Statements made by Ms Berezovskaya were read out to the court by Berkshire Coroner Peter Bedford, in which she claimed there were a number of people who were a threat to the former Kremlin insider.
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Asked what she meant by this as she gave evidence today, Ms Berezovskaya said: "Because he was a target, always. My father was a very serious political figure."
But the inquest at Windsor Guildhall also heard that, in her first statement, given the day after her father was found dead on March 23 last year, she said she thought he had killed himself and had often spoken of doing so.
"It was obvious to me that the cause of my father's suicide was deep depression and severe suffering," she said in the statement.
The inquest also heard that she later wrote a letter to the authorities on behalf of the family, which said it was widely believed he took his own life and therefore "any extended police investigation to us is unnecessary".
Questioned about the contradictions today, Ms Berezovskaya said that, although in the months after his death she was willing to accept that he killed himself, "the more I thought, the more doubts I had".
Yesterday, the inquest heard that Russian exile Mr Berezovsky, 67, became a "broken man" after losing the case against Chelsea owner Mr Abramovich and facing several other costly litigations.
His body was discovered slumped on the bathroom floor with a ligature around his neck at his ex-wife's luxury property in Ascot, Berkshire.
Mr Berezovsky fled Russia after falling out with the Kremlin and became an outspoken opponent of President Putin.
But yesterday the inquest heard that Mr Berezovsky - who survived at least two assassination attempts - saw himself as less of a target after losing the Abramovich case as the damage to his reputation reduced his power and influence.
The hearing was told that another big blow to him in the months before his death was when his partner, Elena Gorbunova - who sat at his side throughout much of his battle with Mr Abramovich - filed a claim against him which had the potential to financially ruin him.
In an undated letter written to police, Ms Berezovskaya said her father "showed all the signs of severe chemical depression" and had been prescribed medication.
She wrote that she and her family feared he would harm himself when he was at his lowest in the autumn of 2012, but he later told her that he thought he would "die naturally within a year as he physically would not be able to carry on the burden any more".
The inquest heard that her letter ended with a criticism of the medical professionals who treated him, questioning if they had done enough to prevent his death.
She asked why he was not advised to have counselling, if he should have been sectioned, why his doctors did not question his cancelled appointments and why he was allowed to stop taking his anti-depressants days before he died.
Asked by Mr Bedford if she still questioned this today, Ms Berezovskaya said it was because she had no previous experience of dealing with someone with depression.
She told the inquest: "Of course, I have the questions to the doctors 'How come we were not told about such high risks?'"
Yesterday, consultant psychiatrist Dr Saeed Islam told the hearing that Mr Berezovsky turned down counselling and could not have been committed to a mental health hospital against his wishes.
It also heard that he stopped taking his anti-depressants because they were having an adverse effect on his liver.
Mr Bedford also referred to a 22-page report submitted by forensic scientist Raymond Fysh, which detailed tests for poisoning including radiation and found no evidence of any.
He did not read it out, but said: "I have never in my experience as a coroner seen any report of this detail of magnitude.
"It concludes there was no scientific evidence from the circumstances of the case as described to him, the post-mortem examination findings, or the scientific tests, that he had taken or had been administered a poison which would have contributed to his death."
Dr Simon Poole, the Home Office pathologist who carried out the post-mortem examination on Mr Berezovsky, said his injuries were consistent with suspension.
Dr Poole was asked by the coroner whether, if Mr Berezovsky had been strangled by someone else, it would have been detected.
He said that, as the businessman was not incapacitated by drugs or alcohol, he would have struggled if suddenly set upon by an assailant, even if this was from behind, and there was no evidence of this.
He added that, if he had been murdered, his body would have become a "dead weight", and therefore it would not have been possible for someone acting alone to have set up the scene in which he was found.