Police in Quang Ninh Province announced they have arrested the ringleader responsible for a vicious knife assault on three plainclothes police officers on Sunday.
Le Thi Lan, 38, was tracked to a hideout in the northern province's Tien An Commune, police said.
The assault took place in the neighboring city of Hai Phong on February 17.
Captain Vu Thanh An, Captain Nguyen Hai Hung, Second Lieutenant Vu Duy Huyen and a fourth, unidentified officer, were escorting a criminal from Quang Ninh's Yen Hung District to Hai Phong City on February 17 afternoon.
While travelling through Rung wharf in Yen Hung District, they encountered a man brandishing a plastic gun at passers-by.
One of the police officers warned the man not to joke like that. The man reacted by insulting the policemen and phoning a woman who rushed to the site and ordered a gang to attack the policemen with knives.
Nearly ten assailants descended on the officers, who were dressed in casual clothing.
After slashing the policemen, the gang fled the scene.
An and Hung suffered head injuries. As for Huyen, the tendon of his left hand and two fingers of his right hand were cut.
The fourth, unidentified, officer maintained custody of the prisoner and transported the injured to a nearby hospital.
All three officers are being treated at Viet Tiep Friendship Hospital in Hai Phong City.