A fourth woman has been arrested over a deadly beating that was reportedly streamed live over the Internet, police said.
Kaori Katsumata, 43, was arrested Monday on suspicion of causing bodily harm resulting in death. Her address and occupation were not released.
Officers at Shinjuku Police Station said Katsumata denied helping the three other women kill Taeko Hashimoto, the 31-year-old female victim, last month in a Tokyo apartment.
The police suspect Katsumata and the three other women attacked Hashimoto for "bad-mouthing" them. The footage that was reportedly streamed over the Internet showed Katsumata and the other suspects repeatedly striking Hashimoto with an iron pipe, the police said.
The three other suspects were arrested earlier.