A 25-year-old woman who was arrested last week for the alleged 2018 murder of her elderly wealthy husband in western Japan is suspected of having planned to sell at least one of the expensive paintings he owned, investigative sources said Thursday.

Saki Sudo asked an art dealer to evaluate the painting owned by Kosuke Nozaki, 77, president of a liquor sales company and real estate business in Wakayama Prefecture who had amassed property worth around 1.3 billion yen ($11 million), the sources said.

Nozaki published an autobiography in 2016 in which he likened himself to the mythical Spanish playboy Don Juan, claiming to have given 3 billion yen to 4,000 "beautiful women."

Photo taken June 4, 2018, shows autobiographies by Kosuke Nozaki. (Kyodo) ==Kyodo

Sudo allegedly made the request after Nozaki's death in May 2018, just three months into their marriage. The man owned several expensive artworks among other luxury items, according to the sources.

They did not say whether Sudo actually received a valuation from the dealer or sold the painting.

Sudo is suspected of causing Nozaki to ingest a lethal amount of an illegal stimulant drug with the deliberate intent to kill him at their home in Tanabe, Wakayama Prefecture, according to the police.

She denied the allegations during voluntary questioning before her arrest on April 28, the sources said. Local police have declined to disclose whether she has made a confession since her arrest.

Sudo, who is from Sapporo on Japan's northernmost main island of Hokkaido, told a friend that she married Nozaki in February 2018 because he agreed to give her 1 million yen every month, according to the friend.

However, she often stayed in Tokyo even after the marriage and Nozaki, unsatisfied with the situation, had asked her for a divorce before the alleged murder, the sources said.

The house of Kosuke Nozaki, dubbed "Don Juan," in Tanabe, Wakayama Prefecture, is pictured on April 28, 2021. (Kyodo)

The police are investigating how Sudo secured money after her husband's death as she moved house several times following the alleged murder before settling down in a condominium in Tokyo's Shinagawa Ward. They sent Sudo to prosecutors on April 29.

Nozaki was found dead at the couple's home with traces of a stimulant drug found in his system but no needle marks on his body, prompting the police to investigate the case as a possible poisoning murder.

Given the notoriety Nozaki had earned through his autobiography, his suspicious death attracted public attention.

The sources said earlier that Sudo researched about stimulants on the internet and contacted a drug dealer.

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