SAPPORO (Kyodo) -- A Japanese court on Wednesday ruled that a man was not guilty of helping his daughter commit murder and behead the victim in Sapporo in 2023.

But he was found guilty of aiding in the abandonment and mutilation of the corpse and sentenced to one year and four months in prison, suspended for four years.

Psychiatrist Osamu Tamura, 61, was on trial at the Sapporo District Court in Hokkaido on multiple charges, including assisting in the murder of a man who had allegedly met his daughter, Runa, 31, at a nightclub about a month before the killing and later had a falling out with her.

Tamura claimed that he "learned about the crime only after it had already occurred."

Prosecutors had demanded a 10-year prison term, arguing that the father was aware of the murder plot about two weeks before it took place when the family held a "discussion" after Runa agreed to meet the victim again.

Tamura "was involved in almost all aspects of the crime and played an integral and important role," prosecutors argued.

Tamura allegedly purchased items such as a saw and suitcase between June and July 2023 that were later used in the murder.

The defense admitted that Tamura purchased the saw and dropped off and picked up Runa near the hotel in Sapporo's Susukino entertainment district, where the killing occurred.

But they said Tamura was merely recording Runa as she handled the victim's head, not assisting in the mutilation of a corpse.

The trial focused on the Tamura's parent-child relationship. The father drove his daughter anywhere she wanted and even slept in a nearby internet cafe as the family home was full of Runa's possessions.

"The fact that Tamura not only tacitly approved her abandoning and damaging the corpse but also made comments that could be interpreted as praise psychologically reinforced the intent to commit the crime," the ruling said.

The victim was 62-year-old Hitoshi Ura, who had been residing in Eniwa, a city adjacent to Sapporo.

Ura was found naked and headless at the hotel on July 2, 2023. Runa, who is facing murder and other charges, allegedly stabbed him in the neck at around 11:15 p.m. on July 1, then beheaded him and took the head home in a suitcase.

His head was later found in the bathroom of the Tamura residence in Sapporo.

Both the prosecution and the defense have alleged that Runa met Ura at a nightclub in Susukino in late May 2023 and that he had engaged in some acts against her will at a hotel.

Runa's mother, Hiroko, is also on trial at the district court on charges including aiding in the abandonment of a corpse.