Ms Kakehi's previous three husbands and three boyfriends were reportedly aged between 54 and 75 when they died.
Each death allegedly took place within a few years of marrying or starting relationships with her.
AFP news agency reported that police are now working on a theory that she had a hand in the deaths of her previous partners.
Media reports have linked Ms Kakehi's partners' deaths to hefty insurance payouts, with one news outlet saying she had received hundreds of millions of yen over the past two decades.
But Ms Kakehi has denied such accusations
またまた発生、婚活殺人事件
うぶな男がまた殺された。
But Ms Kakehi has denied such accusations
女って、こうだよね。
私は悪くない。悪いのはあなた。
私はやってなーい。