A 34-year-old construction worker has been arrested on an initial charge of dumping the corpse of his 24-year old estranged girlfriend in the Sagami River in November in the city of Hiratsuka, Kanagawa Prefecture, and police are probing to determine if he killed the woman, after neighbors said they repeatedly witnessed the pair quarreling.

Seiji Kamioka admitted that he had dumped the body, the police said, quoting him as saying, "I had trouble with her in the car when I drove her back home."

Ayana Yoshida's body was found on Nov. 5 floating on the river. The corpse had been wrapped in two layers of futon, tied carefully with rope and weighted with two stone blocks, indicating Kamioka wanted the deceased to sink to the bottom.

Yoshida died of a fractured skull apparently after being struck by a blunt object. The police are investigating to determine if Kamioka killed her. Kamioka's neighbors said they often saw the two exchanging harsh words in front of his house. It is believed Yoshida also asked acquaintances for advice regarding the relationship.