Selangor police chief Datuk Noor Azam Jamaludin said the suspects, who are the owners of the factory alleged to be the cause of the pollution, were arrested during an operation carried out from 11pm until 12.30am last night.
“The four, aged between 50 and 60 were either picked up from their homes or detained when they reported at the Gombak district police station.
"We will apply for a remand order this morning at the Selayang Court for further investigation," he told Bernama.
He said through initial investigation it was found the four suspects who are brothers, have been running the factory since their father died.
The case is being investigated under Section 430 of the Penal Code.
Yesterday, Selangor Menteri Besar Datuk Seri Amirudin Shari was reported as saying the factory, suspected to be the source of the odour pollution and had caused four Sungai Selangor water treatment plants (LRA) to suspend operations since Thursday, has been sealed and compounded with immediate effect.
He said the factory was alleged to have released solvent into Sungai Gong which flows into Sungai Sembah, one of the main rivers of Sungai Selangor.
A total of 1,292 areas in the Klang Valley, Petaling, Klang/Shah Alam, Kuala Selangor, Hulu Selangor, Gombak and Kuala Langat, involving nearly 1.2 million consumer accounts, were affected by the unscheduled water cut since Thursday, after the four treatment plants ceased operation.