A former chief of Vietnam’s Police General Department has been investigated as legal proceedings were commenced to clarify his role in a giant police-backed online gambling ring smashed last year.

Phan Van Vinh, who retired as director general of the Ministry of Public Security’s police general department, was probed for “taking advantage of positions or powers while performing duties," police said on Friday.

Vinh, a former lieutenant general, is believed to play a role in the online gambling ring that involves more than 70 other defendants, including Major General Nguyen Thanh Hoa, former head of the hi-tech crime prevention division under the Ministry of Public Security.

Vinh, born in 1955 in the northern province of Nam Dinh, was the provincial police chief before being appointed to lead the Police General Department.

He was known for overseeing several high-profile crime cases.

These include the investigation to find an underage culprit that killed all members of a family in a gold shop robbery in the northern province of Bac Giang in 2011, and the arrest of Nguyen Duc Kien, a banking mogul who was in 2014 handed a 30-year jail term for fraud, tax evasion and illegal trade.

A source close to Tuoi Tre (Youth) newspaper said that the ring had been organizing online gambling across nations before being busted by police in the northern province of Phu Tho in September 2017.

Competent agencies have so far confiscated more than VND1.3 trillion (US$57.2 million), while the amount of foreign currency which was sent overseas via the gambling activities was estimated at $3.6 million.

Those involved in the ring are being investigated for organizing gambling, online gambling, and money-laundering.

The ring was led by Nguyen Van Duong, former chairman of CNC, a hi-tech security company, and Phan Sao Nam, former chairman of the VTC Online firm.

According to police investigation, Nam has provided software and copyrighted gambling games for Duong to use on Rikvip and Tip.club, two major gambling sites under his management.