Nguyen Tan Phuoc, 41, a former sub-lieutenant with the Traffic Police Department in the southern province of Dong Nai, was found guilty of "murder" and "illegal use of military weapons."

According to the indictment, Phuoc’s girlfriend opposed a relationship between Bui Viet Hai and her 19-year-old daughter, but had been unable to make them break up.

On January 6 last year, after Phuoc’s girlfriend asked him to bring her daughter home, he decided to take matters into his own hands. He took a gun from the office and went to Hai's place to find his girlfriend’s daughter. After Hai told Phuoc that he didn’t know where she was staying, Hai pulled out the gun and shot him.

Hai was rushed to a local hospital but died later.

In 2010, Phuoc had worked as a driver for retired provincial police chief Nguyen Van Khanh and was given the gun to protect his superior.

Phuoc was then transferred to the Traffic Police Department in 2012 but he didn’t hand over the gun to his superiors as required.

Investigators are clarifying the responsibility in gun management by Dong Nai Police leaders on "lack of responsibility and causing serious consequences."

A draft proposal drawn up by the Public Security Ministry last month recommended that traffic police officers are armed with handguns and even submachine guns.