An Army officer in his late 30s is taken to the Gangwon Police Agency, Monday, for allegedly killing a woman colleague and abandoning her body in Gangwon Province. Yonhap

An active-duty Army officer who was arrested by police admitted to having killed a woman colleague, then mutilated and abandoned her body in the Bukhan River in Hwacheon, Gangwon Province, Monday.

According to the Gangwon Police Agency, the suspect is a senior officer in his late 30s working at the military's cyber operations command in Gwacheon, Gyeonggi Province. He was transferred to an affiliated unit in Seoul's Songpa District last month.

The victim is a 33-year-old woman under a fixed-term contract who worked in the same unit as the assailant until last month.

According to the investigation, he strangled the woman to death in anger during an argument in his vehicle in the unit's parking lot at around 3 p.m. Oct. 25. He mutilated the body on the same day at a construction site under demolition.

Then he dumped the murder weapon along with the body into the Bukhan River at around 9:40 p.m. the next day. He even used stones to weigh the body down in the water.

The man chose the site because he had worked there more than 10 years ago.

Details of the crime began to be revealed Saturday when a local reported that part of the remains surfaced in the river. The investigation took off as the police confirmed the identity through fingerprints and DNA.

Police identified the man from the victim's mobile phone records, analysis of surveillance camera footage and investigation of the victim's family, and arrested him on charges of murder on Sunday in southern Seoul's Gangnam District.

They reported the man did not resist arrest and immediately admitted to the charges.

After investigating, the police plan to seek an arrest warrant for the man on charges of murder, damage and concealment of the body.

While the man said that he committed the crime accidentally during an argument, the police plan to reveal the relationship between the two, the motive of the crime and whether the crime was planned through digital forensics on the man's mobile phone.

Based on the man's statement, police are continuing the search for the rest of the body while considering whether to disclose his personal information.