Pol Col Narat Sawettanant said Mr Porlajee has been missing for seven days after being arrested by Phetchaburi's Kaeng Krachan National Park officers for allegedly possessing illegally harvested wild honey.
Park chief Chaiwat Limlikitaksorn claimed he only reprimanded Mr Porlajee as it was a “small offence” but the man has not been seen since shortly after he was released.
Pol Col Narat said Mr Porlajee’s disappearance was a sensitive issue as he was a key activist fighting a court case with park officials who accused him and indigenous Karen villagers of trespassing on forest land.
He likened the nature of the case to that of Somchai Neelapaijit, the well-known Thai Muslim activist lawyer, given that both men had legal disputes with state officials and went missing after being last seen with them.
The 30-year-old activist’s case had affected Thailand’s human rights protection efforts and the country may face criticism from the international community after its 2012 singing of the International Convention for the Protection of All Persons from Enforced Disappearance, Pol Col Narat noted.
The Convention enters into force in Thailand after it is ratified. Thailand planned to ratify the Convention this year, he added.
Meanwhile, police searching for Mr Porlajee have examined Mr Chaiwat’s pickup truck that was used to carry the father of five to a park protection unit for questioning. They collected fingerprints and hair to be used as evidence.
Hundreds of police and military personnel have been involved in the search for Mr Porlajee in the Kaeng Krachan National Park area but no sign of him has emerged.