A woman has been arrested in Japan for allegedly using a needle and thread to sew her flatmate's lips shut.

Part-time worker Masae Sakurai, 49, was held by police on Monday in Koga over an alleged attack which left her 42-year-old roommate unable to eat or speak.

The incident is said to have happened around 1.30pm on June 29 and the victim escaped the house the following day while Ms Sakurai was out.

Wearing a white face mask, the 42-year-old ran to a nearby shop and handed a worker a note with the words 'please help me'.

The employee contacted police, who were later told by the woman that she decided against fleeing sooner out of fear, saying: 'I was afraid of Sakurai, so I couldn't escape right away.'

Officers said they were investigating the motive and circumstances behind the attack as well as the relationship between the two women.

It is not known whether Ms Sakurai had admitted to or denied the allegations.

The pair lived together at Ms Sakurai's house since April 2025, Japanese media reported. 

It is believed that other people were in the property at the time of the attack.

Ms Sakurai had a history of letting people who had left their homes stay with her and helped some find work, acquaintances told local broadcaster TV Asahi.

Local media reported that a 54-year-old acquaintance who used to work with Sakurai visited her home in November, and had seen 'two or three women and a male around the age of a junior or senior high school student.'

And a 49-year-old former colleague said she learned around three years ago that the suspect was 'taking care of girls who have nowhere to go after reaching out to their parents.'