National police chief Pol Gen Damrongsak Kittiprapas said he will take charge of the investigation into a criminal syndicate linked to Chinese businessman and suspected crime boss Chaiyanat "Tuhao" Kornchayanant.
Pol Gen Damrongsak said the move is in response to criticism by former politician and massage parlour tycoon Chuvit Kamolvisit regarding the investigation. He says police have been too slow to act.
He said Mr Chuvit keeps leaking information to the public about a Chinese gang allegedly involved in the matter, and bribe-taking in the immigration service. Mr Chuvit has also accused the police of dragging their feet on the investigation, he said.
"To prevent misunderstandings over what Mr Chuvit said regarding the police investigation, I will closely supervise and direct the investigation," Pol Gen Damrongsak said.
"I strongly believe this investigation is for real, not for show as accused."
Previously, Pol Gen Surachate Hakparn, the deputy national police chief, was assigned to supervise the investigation, which was being handled by a police investigation team headed by the commissioner of the Metropolitan Police Bureau, Pol Gen Damrongsak said.
As for the investigation's progress, so far nine key suspects, including Mr Chaiyanat, have been arrested, he said.
He also dismissed a claim by Mr Chuvit that only six people had undergone urine drug tests on Oct 26 when the police raided the Jinling pub in Bangkok, the operation that marked the beginning of this investigation.
A total of 104 people tested positive for drugs at the scene, while only 77 were later confirmed by drug tests run by Thanyarak Hospital, he said, adding 66 of them admitted to using drugs while the rest denied any wrongdoing.
One of the 77 drug suspects fled while the rest are facing prosecution, he said.
"The police are widening their investigation, seizing assets linked to the gang and tracking more suspects believed to be involved," he said.