Dang Anh Tuan, 49, is being investigated for taking undue advantage of his position and authority.

Police also carried out a search of his residence and workplace in Hanoi on Thursday.

The probe into Tuan, who has been the ministry’s chief inspector since April 2015, continues investigation of the online gambling case busted last year that has already seen several big heads roll.

According to police in the northern Phu Tho Province, who busted the case, an inspection team from the information ministry had already found signs of the online gambling being organized back in October 2016, but as chief inspector, Tuan did not report the findings to higher authorities and even suggested that the then minister stops the inspection.

Tuan’s actions and inactions allowed the violations to continue until they were detected by the police.

A court concluded last year that the ring operated under the protection of two top police officials.

Investigators found that Phan Van Vinh, former director of the General Police Department under the Ministry of Public Security, had helped Nguyen Thanh Hoa, former director of the ministry’s Department for High-Tech Crime Prevention and Nguyen Van Duong, chairman of high-tech security development company CNC, to set up the gambling ring, which has generated a total income of over VND9.8 trillion ($426 million) and a profit of VND4.7 trillion when it was busted.

Duong had previously been working with Hoa’s division to provide technical support before setting up the gambling service in May 2015 with Phan Sao Nam, founder and former board chairman of major online communications firm VTC.

According to investigators, the gambling ring headed by Nam and Duong on web portals Rikvip/Tip.club had established a large network of 25 "tier 1 agencies" and nearly 5,900 "tier 2 agencies" with nearly 43 million user accounts since being launched in mid-2015.

The illegal ring was found to The ring was first uncovered when Phu Tho police were investigating a fraud case involving mobile top-up cards in May 2016. The scammer in the case claimed he had redeemed all the cards for virtual currencies used in an online gambling card game.

Investigating this claim, police discovered Nam and Duong's ring, which was run using the two online game portals that resembled professional casinos in which players could gamble virtual money and convert their winnings to real money.

At the trial last year, Vinh and Hoa were found guilty of "abusing power or position in the performance of official duties."

Vinh got nine years in jail while Hoa was sentenced to 10 years. They were also fined VND100 million ($4,300) each. Vinh was arrested in April 2018 and Hoa a month earlier.

The trial also involved 90 other defendants who were charged with organizing gambling, money laundering, illegal trading of invoices, and using the internet to appropriate assets.

Of those, 17 were fined VND40 million each, 22 got probation and the rest received up to three years in jail.