A 67-year-old woman who reportedly received millions in life insurance money from at least five of her previous partners has been arrested on suspicion of poisoning her last husband with cyanide -- the latest high-profile case in Japan involving so-called `` black widows . '' Chisako Kakehi , who benefited to the tune of 800 million yen ( $ 6.8 million ) over the past 20 years , according to Japanese media , denies any wrongdoing . `` I did n't kill him . I do n't know how to kill ... '' she told police , according to CNN affiliate TV Asahi . But an autopsy report on Isao Kakehi , her fourth husband to die , found cyanide in his stomach and blood . The 75-year old died in December , less than two months after their wedding . It triggered a police investigation into the case , which culminated in Kakehi 's arrest in Kyoto on Wednesday . A previous fiancé , who died when he crashed his motorcycle , was also found to have traces of cyanide in his body . Police would only say `` many '' of her previous partners -- who were aged between 54 and 75 -- had died in the past two decades . Autopsies rare . However , authorities may be unable to prove she killed her other lovers because autopsies are generally rare in Japan . Her first husband died back in 1994 . Kakehi is the latest `` black widow '' to make the headlines in Japan . Kanae Kijima is currently in prison after being found guilty of killing three men she met on dating websites in 2009 and making it look like suicide in each case . She was 37 at the time . That same year , bar worker Miyuki Ueta , 40 , was found guilty of drugging and drowning two men she reportedly owed money to . Both are appealing death sentences .
Seven of Ms Kakehi 's previous partners have died in recent years . Autopsy results on her fourth husband found cyanide in his blood , police said . Media reports say she has made money from life insurance money .