The graft probe against the former director-general of the Department of National Parks, Wildlife and Plant Conservation (DNP), Rutchada Suriyakul Na Ayutya, has concluded, the police announced on Monday.
Anti-Corruption Division commander, Pol Maj Gen Jaroonkiat Pankaew, said on Monday the results of the probe have been handed over to the National Anti-Corruption Commission (NACC).
He said authorities are considering setting up a joint committee comprising police and officers from the NACC and the Public Sector Anti-Corruption Commission to further investigate Mr Rutchada, who has been charged with demanding bribes and malfeasance in office.
As the police have solid evidence against Mr Rutchada, Pol Maj Gen Jaroonkiat said he was confident that the former DNP chief would be indicted and found guilty.
Mr Rutchada was arrested at his office in Chatuchak district on Dec 27 on suspicion of demanding or taking bribes from his subordinates. An envelope containing 98,000 baht was found during his arrest, while envelopes containing a total of 4.9 million baht with the names of his subordinates were found in Mr Rutchada's safe.
According to police, a total of 36 witnesses have been questioned, including 14 people whose names appeared on the envelopes.
The arrest followed a complaint by Chaiwat Limlikit-aksorn, former head of Kaeng Krachan National Park in Phetchaburi, who accused the department chief of abusing his authority by transferring officials who refused to pay him 500,000 baht.
Mr Chaiwat, who on Monday gave his statement to the NACC, urged the NACC to conclude the investigation within 30 days as he claimed several witnesses had been intimidated by people close to the suspect.
He also said witnesses were also concerned about the impartiality of the disciplinary panel because some members have been closely linked to Mr Rutchada.
Sornchai Chuwichian, assistant to the NACC's secretary-general, said the agency would set up a panel to examine the case, and whether or not it will summon witnesses for questioning will depend on the evidence police had gathered.
Niwatchai Kasemmongkol, the NACC secretary-general, said the NACC's inquiry is likely to be concluded in one year if all witnesses agree to cooperate.
He also warned officials involved in the case to tell the truth or face charges of colluding to commit malfeasance.