Gunnar Wall, a journalist who wrote a book about the Palme murder, told the Kvällsposten newspaper that Rausing contacted him on Wednesday to tell him that his wife Eva’s claim that he had told her who killed Palme was “completely untrue”.
Wall told the paper that Rausing referred to her claim as a “baseless conspiracy theory”.
The two were in touch first by text message and then a brief phone call, Wall said.
Swedish prosecutors said last month that Eva Rausing had contacted them before her death this summer, but did not disclose what information she had provided or whether they considered it pertinent.
Wall last month told Swedish newspaper Dagens Nyheter that Eva Rausing had contacted him before her death and claimed to know, via information obtained from her husband, that a Swedish businessman had had Palme killed because Palme posed a threat to his business.
She said her husband had found out by coincidence and that she believed she knew where the murder weapon was.
Palme was shot dead by a lone gunman on the evening of February 28, 1986, shortly after leaving a cinema in central Stockholm to walk home with his wife Lisbet.
The murder has never been solved despite hundreds of thousands of leads over two-and-a-half decades.
Sweden in 2010 scrapped its 25-year statute of limitations on murder, and the investigation continues.
Over the years, investigators have suspected Turkish Kurd rebel group PKK, the Swedish military and police, and the South African secret service among others.
A petty criminal, Christer Pettersson, was convicted of the crime in July 1989 after Palme’s widow identified him in a widely-criticised line-up.
He was however set free months later by an appeals court due to lack of evidence. Pettersson died in 2004.
Wall told Expressen that Hans Kristian Rausing gave a “calm and collected impression”.
Hans Kristian Rausing recently made headlines after leaving his 48-year-old
wife’s dead body to decompose in their London mansion for two months. A post mortem found she had drugs in her system, including cocaine.