Prime Minister Nguyen Xuan Phuc signed a decision on Tuesday to suspend Chung for 90 days.

That came the same day as a decision by the Politburo, the Communist Party's decision-making body, to suspend Chung from his title as Deputy Secretary of Hanoi's Party Committee to "verify and investigate to clarify the responsibilities of Chung in a number of criminal cases under existing laws."

Major General To An Xo, spokesman of the Ministry of Public Security, said investigators are clarifying Chung's involvement in three cases in Hanoi.

One case regards "smuggling, accounting violations, laundering and bidding violations causing serious consequences" at Hanoi tech giant Nhat Cuong Technical Services Trading Co. Ltd, for which 28 people including several Hanoi officials are facing charges.

Nhat Cuong's General Director Bui Quang Huy, who is wanted by police, is accused of leading an organized crime group responsible for cross-border smuggling and maintaining two sets of accounting books to conceal trillions of dong worth of revenues (VND1 trillion = $43.17 million).

The second case that Chung is allegedly involved in regards "violations in the use and management of public assets causing waste and losses" at Hanoi People's Committee and related agencies.

Another case regards the appropriation of state secret documents, for which Chung's chauffeur Nguyen Hoang Trung was detained on July 22 together with Nguyen Anh Ngoc, deputy head of the editorial secretariat agency under the Office of the Hanoi People’s Committee, and Pham Quang Dung, an official in the anti-corruption police department under the Ministry of Public Security.

Chung, 53, born in the northern Hai Duong Province, has a doctorate degree in law and a bachelor’s in economics. He spent several years working at the social order-related crime investigation unit at Hanoi Police Department.

He climbed from deputy head to head of the unit before holding the position of deputy director of Hanoi Police Department and heading its investigation agency.

In September 2012, as a major-general, he became director of the city police department.

In late 2015, he was appointed chairman of the Hanoi People’s Committee to complete the 2011-2016 term after his predecessor Nguyen The Thao resigned.

In mid-2016, Chung was re-elected into the position for the 2016-2021 term.

In his speech on taking office, Chung pledged to "act resolutely, creatively and closely with all grassroots (stakeholders) in the system, stay close to the people, devotedly serve the people, seriously listen to people's opinions and aspirations."

Under his stewardship, Hanoi has planted a million trees, renovated hundreds of polluted lakes and executed projects to revive some heavily polluted waterways, including the renowned To Lich River that has been reduced to a stinking sewage canal.

Other highlights of his tenure include Hanoi successfuly striking a deal to host the nation's first Formula 1 race, which has been slated for November this year after months of delay due to the pandemic, and expansion of the pedestrian-only zone around the iconic Sword Lake.

Chung also made critical calls to help Hanoi control the Covid-19 outbreak, bringing the city out of being a locality that led the nation in number of infections and keeping it clean of new community transmissions for 105 straight days.

However, Hanoi still has many issues left unresolved, some that have worsened, including air pollution, urban flooding, traffic jams, renovation of old apartment buildings and complicated land disputes, with a notable one being the case in Dong Tam Commune of My Duc District that led to the deaths of two civilians and three police officers last January.