The Office of Narcotics Control Board has denied any business motive behind the marijuana-related charges on the Khaokwan Foundation chairman and his associate.
ONCB Niyom Termsrisuk said on Monday the charges against chairman Daycha Siripatra and his aide, Pornchai Chulert, were in line with the law, since the foundation has not received permission to possess cannabis and make drugs from the plant.
He also denied speculation that the legal action against the two and the raid at the foundation in Muang district of Suphan Buri were aimed at discouraging small producers from making drugs extracted from marijuana so that big pharmaceutical firms could control the potentially lucrative business.
Supporters of Mr Daycha accused the anti-drugs agency of launching the operation with a hidden agenda to favour big businesses planning to monopolise the marijuana extraction industry.
The case was conducted with without regard for any group or individual, the ONCB chief said. Authorities would face a charge of negligence of duty if they turn a blind eye to the issue, he added.
Anti-narcotics officials led security personnel in a raid at the foundation on Wednesday. They seized marijuana plants, medicines and equipment used to extract cannabis for oil.
Police later charged Mr Daycha and Mr Pornchai with illegally possessing marijuana and producing products from the plants. Mr Pornchai is detained at the provincial court in Suphan Buri, while charges will be pressed against Mr Daycha after he returns to Thailand from Laos.
Advocacy group Biothai on Monday posted a Facebook message opposing the charges, saying the foundation hands out the medicines made from marijuana to patients for free. Mr Pornchai "should not be detained even for a day," it added.
The crackdown on the foundation started when authorities found Vachiraphothiyan Monastery Temple in Pho Thale district of Phichit was one of several locations where oil and capsules made from marijuana were given to patients. They searched the temple and tracked the production back to the foundation in Suphan Buri.
Supporters of Mr Daycha and the foundation have argued that it has produced the marijuana-related medicines for years, and according to the law it has until May 19 to file a registration application with authorities for using cannabis for medical purposes.
Only the Government Pharmaceutical Organisation and the Department of Thai Traditional and Alternative Medicine have been authorised to produce marijuana for medical purposes so far, according to the ONCB.
Public Health Minister Dr Piyasakol Sakolsatayadorn discusses the new medical marijuana law.
Hundreds of patients and their relatives were disappointed after they went to the temple in Phichit to collect the medicines on Monday, only to find the gate had been closed since Sunday with no explanation.
The patients had travelled from Phichit and other provinces, including Lampang, Kamphaeng Phet, Nakhon Sawan and Phetchabun -- especially to receive the oil or capsules for free to treat their illness.
The temple gate bore a single sign reading: "From now on, Vachiraphothiyan Monastery Temple will no longer distribute herbal medicines."
"This is the fifth time I have come here for the oil," said a woman with breast cancer who declined to identify herself. "My condition has improved. So I brought other people along this time.
"I did not know that the temple had closed until I arrived," she said.
Another woman identified only as Khamphan said she had taken 10 capsules from the temple and her rheumatoid condition had improved.
"Now I can move my fingers and make a fist," she said. "I could not do that before I took the medicine. My fingers used to hurt and my hands were swollen."