A millionairess has been arrested on suspicion of poisoning her husband with cyanide, as it emerged he was her seventh partner to have dropped dead in two decades.

Chisako Kakehi, 67, has been the beneficiary of a combined 800million yen (£4.3million) in insurance money and other assets received after the deaths of her seven exes.

If she is found to have been behind the deaths of her partners, she will become the latest example in Japan of a 'black widow', named for the female spider that devours its mate after coupling.

'Doomed by fate'? Japanese millionairess Chisako Kakehi, 67, is arrested in Kyoto on November 19 on suspicion of poisoning her husband with cyanide in the latest 'Black Widow' case

Husband number four Isao Kakehi fell sick suddenly at home and was confirmed dead at a hospital in December last year, less than two months after the couple married.

A post-mortem examination found highly toxic cyanide compounds in his blood.

That came after the September death of a 75-year-old boyfriend, who fell suddenly ill after the couple ate together at a restaurant, Jiji Press reported.

Kakehi's dalliance with death began in 1994 when her first husband passed away at the age of 54.

In 2006 her second husband, whom she had met through a dating agency, died of a stroke aged 69, while the third marriage ended in 2008 with the death of her 75-year-old partner, Jiji said.

A boyfriend, believed to have been suffering from some form of cancer, died a year later, and in 2012 her then-fiance met his fate after collapsing while riding a motorbike.

Traces of cyanide were detected in his body, media reports said.

'Black widow': Kakehi pictured in March. She has previously insisted she was not involved in the deaths

Kyoto, Japan: If Kakehi is found to have been behind the deaths of her partners, she will become the latest example in Japan of a 'black widow', named for the female spider that devours its mate after coupling

Kakehi was arrested on Wednesday by police in Kyoto on suspicion of murdering her latest husband. She has denied any involvement in his death.

'We suspect she did it for money,' said a detective investigating latest death, without giving details of the amount involved.

Lonely hearts killer: In 2012 Kanae Kijima was sentenced to hang for murdering three men - aged 41, 53 and 80 - she met through internet dating sites

Police are now working on the theory that she may have been behind the deaths of at least some of the other six.

'We can't say how many now... Given their advanced age, we have to proceed carefully to judge whether their deaths were actually the result of foul play or not,' the investigator told AFP by phone.

Questioned by reporters earlier this year, former bank worker Kakehi protested her innocence.

'If people suspect murder, I'd find it easier to bite my tongue off and die,' she told reporters in March.

Jiji Press quoted her as saying in an earlier interview that she was 'doomed by fate' to suffer a series of deaths among those close to her, and protesting that she had no access to poison.

Japan has seen several 'black widow' multiple murderesses in recent years. In 2012 Kanae Kijima was sentenced to hang for the murders of three men, aged 41, 53 and 80, whom she met through internet dating sites.

Kijima, who was at one time a paid-for mistress, poisoned her victims with carbon monoxide by burning charcoal briquettes after drugging them with sleeping tablets.

She is in jail awaiting the outcome of an appeal to the supreme court.