Police in the southern province of Binh Duong Tuesday arrested a man on suspicion of involvement in the attack on a member of the local voluntary anti-crime club the day before.
The incident has drawn concerns about the police's capacity to protect people acting voluntarily in public interest.
Vu Van Tuan, also known as "Tuan the dog," is suspected to have led three other people in the attack on Nguyen Dang Tien, member of the crime-fighting club based in An Binh Ward, Di An Town. Tien was slashed with knives and sustained serious injuries in the attack that happened early Monday morning.
The 34-year-old Tuan is said to have attacked Tien and threatened the club's members because the latter had previously helped police bust several cases of thefts conducted by his gang.
However, Di An Town's police maintained that initial investigations did not turn up conclusive evidence that the attack on Tien was related to the case where he and his fellow members helped local police arrest six people suspected of stealing and trading in motorbikes last Saturday.
The people were released later the same day due to lack of evidence, according to police, who said they would continue probing the suspicions further.
But, Thanh Nien reporters Tuesday found that all the suspects had moved out of their rented houses in Binh An Ward one day earlier.
The owner of one of the houses, Tran Thi Ha, told Thanh Nien that she didn't know when they moved out and where they'd moved to. She said two of them were a married couple who'd rented a room in her house nearly four months ago, and the other four visited her house frequently.
When asked about previous statements made by the police that the suspects would be kept under observation, Tran Nhut Hieu, deputy chief of Di An police division, said the case was still under investigation and refused to give further comments.
Do Kim Tuyen, chief of the Criminal Police Department under the Ministry of Public Security, said his department has ordered its southern division to cooperate with Binh Duong's police in investigating the case.
Tuyen said he was especially concerned because it was a "critical" case.
"The department wants to deal with it strictly and quickly and we will propose judicial agencies to consider it as deterrence," the official said.
Meanwhile, Tien, who was transferred from Thu Duc District Hospital in Ho Chi Minh City to the Binh Duong General Hospital Tuesday afternoon under close police protection, insisted that Tuan was one of the people who attacked him.
He said last Friday, after he and his fellow members had helped police arrest another four people suspected of stealing motorbikes, Tuan came to make threats against them.
According to Tien's fellow volunteers, the police released the suspects although they were arrested along with evidence as well as witnesses.
Thanh Nien reporters found that Tuan, who hails from the central province of Nghe An, has been in jail several times for various crimes. His gang mainly steals properties, trades in stolen motorbikes and extorts money through illegal protection rackets at the local Lam Hong bus station.
While investigations into the case are ongoing, the attack on Tien has distressed other voluntary crime fighters.
Tran Hoang An, a member of the voluntary anti-crime club in Thu Dau Mot Town, said: "We don't fear danger, because we believe that we have laws and people to protect us.
"But after the attack on Tien, many of us have felt discouraged because criminals act freely, carrying weapons, to find us and attack us as if they are openly challenging the law.
"It's sad and discouraging."
Another volunteer said it wasn't the first time criminals were taking revenge on them. Nguyen Thanh Hai, another member of Thu Dau Mot Town's Club, had been attacked earlier, he said.