Police on Saturday arrested a man suspected of being the mastermind behind last week's kidnapping and murder of a woman.

The Seoul Central District Court issued an arrest warrant for the suspect, only identified by his surname Yoo, on the charge of murder for hire in the wee hours, saying he might flee or destroy evidence.

The Suseo Police Station in Seoul also apprehended his wife on the same charge later in the morning.

They are acquaintances of one of three previously arrested suspects involved in the death of the 48-year-old woman, according to the police.

The suspects allegedly kidnapped her in Gangnam, southern Seoul, on March 29 to steal her cryptocurrency assets. They allegedly killed her the following morning and buried her body on a hill in Daejeon, 140 kilometers south of the capital.

Yoo and his wife, surnamed Hwang, are said to have given 40 million won (US$30,400) to Lee Kyeong-woo, one of the suspects, in 2021. The police believe it was a down payment for the crime.

Following the murder, Lee, who allegedly planned and led the crime, requested an additional 60 million won from the couple, according to the police.

Yoo admitted to meeting Lee recently but denied any involvement in the case.

Lee and Hwang have had a close relationship since a 2021 criminal case related to their cryptocurrency investment, which also involved the murdered victim.

Lee, the victim and Hwang were co-investors in a cryptocurrency in 2020-21.

After the digital currency fell sharply in February 2021, Lee, the victim and other investors believed Hwang manipulated the token's price. They extorted 190 million won worth of cryptocurrency coins from her.

Lee and the victim were investigated by police for blackmailing Hwang, and only Lee was transferred to the prosecution for further investigation.

Source: Yonhap News Agency