Japanese police have arrested a 49-year-old woman on suspicion of assault after she allegedly used a needle and thread to sew shut the lips of her 42-year-old roommate in the city of Koga, Ibaraki Prefecture. The incident is said to have occurred on 29 June, and the suspect, identified as Masae Sakurai, was taken into custody on 6 July, according to local authorities.

The victim escaped the residence the following afternoon while Sakurai was away. Unable to speak or eat because of her injuries, she wore a white face mask and walked to a nearby shop, where she handed a staff member a note reading “Please help me.” The employee contacted police. The woman later told investigators that Sakurai had become angry after a dispute and sewed her lips, and that she had been too frightened to flee earlier.

Japanese media reports, citing neighbours and acquaintances, describe a household that may have sheltered multiple people. Sakurai is said to have regularly taken in individuals who had left their homes, sometimes helping them find work. The two women had been living together since around April 2025, and police are now questioning other occupants believed to have been present at the property around the time of the alleged assault. Authorities have not confirmed how many people were staying in the house or whether anyone witnessed the incident.

The investigation remains active. Police have not indicated whether Sakurai has admitted to the allegation, and the precise nature of the relationship between the two women is still being examined. No further details on the victim’s medical condition have been released.