Suspicion is mounting that a Kyoto Prefecture woman under arrest for allegedly killing her husband may have also killed previous spouses and lovers.

Chisako Kakehi, 67, was arrested Wednesday on suspicion of murdering Isao Kakehi, 75, who died last December in his home in Muko, Kyoto Prefecture. The Kyoto Prefectural Police found traces of cyanide in his body.

Investigators said they also detected a trace of cyanide in personal belongings that Chisako Kakehi disposed of, and suspect she used the poisonous substance to kill her husband. They are searching to determine how she obtained the cyanide.

She has denied the allegation. Police quoted her as saying, “I absolutely didn’t kill (my husband).”

Despite Kakehi’s denial, mysterious deaths surround her.

Investigative sources said Thursday they have found empty medicine capsules and thin papers for taking medicinal powder in a separate residence she maintains in Sakai, Osaka Prefecture.

The police suspect she may have used them to wrap cyanide or laced food with the substance so that her husband would not notice the poison.

They said they also found several books on medicine in the home.

The sources said Kakehi tried to buy sleeping pills for her husband at a drug store before his death in late December, but eventually bought Chinese herbs with similar effects because she did not have a prescription for the pills.

The police suspect that she had the husband take the Chinese herbs, followed by a capsule of cyanide.

Kakehi is believed to have been married four times. The police said that in addition to her latest husband, five men in Osaka, Hyogo and Nara prefectures related to her have died since 2006.

All four of the husbands and the two men she was dating died several years after they married her or became acquainted with her, they said.

She is believed to have inherited assets totaling more than ¥100 million from the deaths.

Police have already found a trace of cyanide in the body of a 71-year-old man in Kaizuka, Osaka Prefecture, who died in March 2012. They allege the man had a close relationship with Kakehi and are trying to determine how he died.

Investigators say the man fell down on a road in Izumisano, Osaka Prefecture while he was riding a small motorcycle and subsequently died. Heart failure was blamed, but after Isao Kakehi’s suspicious death, police re-examined a blood sample taken from the Kaizuka man and found traces of cyanide.

They suspect she induced Isao to take cyanide on Dec. 28. He he died that day at about 9 p.m.

The police suspect Chisako Kakehi induced her latest husband, Isao Kakehi, to take cyanide at home in a yet-to-be determined method last Dec. 28, causing him to die at about 9 p.m. that day.

According to Chisako Kakehi’s account to the police, she found him collapsed near the entrance to the room, and she called for an ambulance about 50 minutes later.

The police detected an amount of cyanide far exceeding a fatal dose in his stomach and blood but did not find any traces around his mouth. This has led the police to believe Chisako Kakehi may have tricked him into ingesting the cyanide without being aware of it.

After they started to search various locations, one of her acquaintances said she may commit suicide. The police arrested her on Wednesday morning.