Police in the port city of Hai Phong on Wednesday said they had pressed charges against a man for producing pen-shaped guns that have been used in several murders since 2008.
The guns fire 5.56-millimeter bullets and cost less than VND300,000(US$16) to make. They can be sold for around VND4 million, local newswire Vnexpress reported.
Police aim to bring the gun maker, Vo Tien Dat, to court for illegally producing and storing military weapons. Investigators also said Dat was a known drug addict.
The 24-year-old was caught in March with six guns and three bullets.
Dat had borrowed a gun from his friend Pham Quang Tu, 33, and followed the model to make his own.
He hired different small factories in the area to make parts to avoid being recognized. Then he put them together and sold them on the black market.
A local named Dang Huu Minh had been asked to make the head, tail and body of the gun that can kill from 5 meters away.
"Someone brought metal pieces before Tet (mid-February this year) and asked me to lathe them. I didn't know what they were and I was just interested to have something to do. That person came several times, each time bringing a piece of metal," Minh said.
Nguyen Van Tuan, another local, made furrows on the gun body. Minor parts such as springs or screws, Dat bought on the market himself.
He made more than ten guns since late 2009. He had sold four to local Nguyen Anh Duong, 33, his partner in the ring. Duong is currently on the run from police.
Dat said he sold the guns to have money for heroin.
Hai Phong has reported six murders caused by pen-shape guns since late last year, according to police figures.
Nguyen Tien Cong, whom police describe as a known murder among Hai Phong gangsters, recently used pen guns, investigators said.
The guns are cheap and easy to use as discharging a round was as easy as a light tap on the head of the pen.
Cong killed local Pham De Khang with a pen gun on May 2 at the victim's house.
According to the police, Dat is the first to produce pen guns in Vietnam but such guns smuggled from China had been found in Hai Phong at least two years ago in February 2008.
Police records showed that Du Kim Dung, 42, a Hai Phong ectasy "boss", was caught with two pen guns that he always carried.
Dung had bought the guns from Nguyen Minh Chi, 53, who had bought them from Pham Cao Son, 44.
Chi was caught later in late March with one pen gun and Son with four. A search of Son's house found another two pen guns among 20 guns and many gun parts.
Son got two years in jail and Chi one and a half years after a trial in December 2008 at Hai Phong People's Court.
Tran Thai Duc, younger brother of Hai Phong gang leader Tran Thanh Long, was caught in November last year with two pen guns.
The guns have become familiar with ordinary young men in Hai Phong as well. The police last month caught Doan Xuan Nam, 20, with a loaded pen gun.
Do Huu Can, deputy director of Hai Phong Police, said pen guns were "very dangerous" and easy to hide.