Vo Tien Hung, general director of the Hanoi Sewerage and
Drainage Company. Photo by VnExpress/Ba Do. 

The general director of state-owned Hanoi Sewerage and Drainage Company has been detained for alleged violations in monopolistic acquisition of a lake cleaning agent. 

Vo Tien Hung has been detained to be investigated for "offences against regulations on the management and use of state assets that lead to losses or wastefulness," To An Xo, chief of staff and spokesman of the Public Security Ministry said Thursday.

Authorities have accused Hung of being involved in the monopolistic acquisition of Redoxy-3C, a water cleaning agent, to clean up over 100 lakes in Hanoi.

The probe into Hung is part of a developing investigation, also for violations of state assets management, at the Hanoi People's Committee and relevant agencies, which began earlier this year.

It is also one of three criminal cases involving Hanoi People's Committee Chairman Nguyen Duc Chung that are being investigated. He was suspended from his position for 90 days earlier this month pending investigation of the cases.

In 2016 Chung had commissioned a German company to research and produce cleaning agents for the capital's 100-odd lakes. In July that year the company created Redoxy-3C and Chung instructed the Hanoi Sewerage and Drainage Company to use it to clean up the city’s lakes.

This was considered "a tech product monopolized by the Hanoi People's Committee".

Questions about the deal and effectiveness of Redoxy-3C prompted city inspectors to open an investigation in May last year.

They found that the drainage company had bought over 400 tons of the substance from the German firm for VND137.6 billion ($5.94 million) and used 380 tons, but stated that there was no evidence of wrongdoing.