Iran's state-run English language TV channel has shown a documentary on Sakineh Mohammadi Ashtiani, sentenced to death by stoning for adultery.
In a 25-minute programme, Ms Ashtiani confessed to and re-enacted her alleged part in the murder of her husband.
She was shown with a needle, indicating where she gave him an injection.
The documentary, broadcast on Press TV, followed foreign media reports that Ms Ashtiani had been freed. She was originally sentenced to death in 2006.
Her plight came to international prominence earlier in 2010 when it emerged that she was to be executed by stoning as punishment for adultery, after appeals for clemency were denied.
Campaigners in many countries have called on Iran's authorities not to carry out the sentence.
They stress she remains in prison, and that her fate is still unknown. Both her son, Sajad Ghaderzadeh, and her lawyer, Houtan Kian, are under house arrest.
In the face of strong international pressure Iran said the stoning sentence had been suspended, but said Ms Ashtiani still faced a death sentence for the murder of her husband.
In what Press TV described as an investigative report, Ms Ashtiani was shown supposedly confessing how she first drugged her husband by injecting him with a needle at their home in the small town of Oskou in north-west Iran. When the husband was unconscious, she said, her alleged lover, Isa Taheri, electrocuted him.
"My husband had been unconscious for about 20 minutes when Isa called and asked me whether he was conscious or not," said the 43-year-old mother-of-two.
"First he tied a wire to his foot and another one to his waist. When Isa connected the wire to the socket, the electricity went out.
"Isa electrocuted my husband six times but he hadn't died because he still moved. But the seventh time he didn't move."
Correspondents say Iranian media have been portraying Ms Ashtiani as a common murderer, rather than an adulterer, as a way of trying to deflect international pressure over the stoning sentence.
Press TV's programme did not fully answer the question about whether she would be executed.
It repeated the current government position that Ms Ashtiani's case was still going through Iran's legal system and that there was a good chance her life may be saved.
Reports in international media that she had been freed followed a statement on Thursday from The International Committee Against Stoning that it had "received reports of the release of Sakineh Mohammadi Ashtiani and her son".
The Germany-based campaign group said it was awaiting confirmation from Iranian authorities.