A 22-year-old woman was fatally stabbed Wednesday on a street in Chiba Prefecture and the assailant remains at large, police said.

Shiori Yuasa was stabbed in the abdomen, apparently with a kitchen knife, at around 4:30 p.m. in a shopping district in the city of Ichikawa and was pronounced dead at a hospital. A passerby alerted police, investigators said.

Yuasa's 35-year-old boyfriend, who was with her when she was attacked, told investigators that the male assailant ran away with a kitchen knife measuring 20 to 30 cm.

Witnesses said the man ran upstairs leading to JR Motoyawata Station, the police said.

The assailant is described as around 20 to 30 years old and 170 to 175 cm tall. He was wearing black clothes, jeans and a black knit hat, according to witness accounts.

In September, Yuasa told police she was in trouble after her former boyfriend pressed her to get back together. She also said she had money trouble with another man.

Police said they have been checking footage from security cameras at train stations to track down the assailant.