The search team comprised narcotic suppression police, soldiers and corrections department officials. Pol Col Chatree Paisalsilp, deputy commander of the Narcotic Suppression Bureau, and Prasert Yusupharp, the governor of the prison, led the raid.
The operation targeted Zone 2 of the prison where 841 major drug offenders are jailed. Many apprehended drug traffickers had said they received orders from prisoners in this zone.
Instead of finding any drugs or other illegal objects, the officials found a few bank passbooks recording savings worth about 150,000 baht, 6,000 baht in cash, mobile phone SIM cards, notebooks recording sums of money and phone numbers, and cough medicine.
The passbooks were buried near a bathroom. Officials will check if the cough medicine had been adulterated with drugs.
Mr Prasert, the prison governor, said prison searches had started on June 9 as ordered by the National Council for Peace and Order and officials seized 16 mobile phones, 0.5 grammes of crystal methamphetamine or "ice", and a number of sharpened steel rods.
He said he would do his best to block attempts to send prohibited objects to prisoners.