Police in the central province of Nghe An on Monday suggested charging a driver's assistant with "accidental killing" after he allegedly pushed a passenger off the bus and to his death.

The police of Quynh Luu District of the province have arrested Nguyen Thanh Nghia and are investigating whether or not he pushed Le Hung Cuong off the bus during an argument that ended in Cuong dying in the hospital after he fell from the moving vehicle last Monday.

Nghia's bus had agreed to drive Cuong's children Le Thi Nga and Le Van Viet to colleges in Ho Chi Minh City for VND1 million (US$52). It transferred them to another bus more than an hour later and the second bus forced them to give up another VND200,000.

Viet called Cuong to inform him of the problem. Cuong and three others caught Nghia's bus, at the time going back northbound, and climbed up as normal passengers. But then they argued and the 47-year-old father fell off the bus some 100 meters later.

Investigators found that there had been some kind of fighting between Nghia and Cuong near the bus door.

Nghia was 30 years old, coming from Bac Lieu Province in the Mekong Delta.

The bus driver Pham Hong Quang from the northern province of Ninh Binh has also been detained for investigation, the newswire Vietnamnet said Monday.