Deputy CSD Commander Pol Col Prasobchok Prommoon today inspected the detention of Mr Veera and seven other activists who were arrested during their walk campaign for Thai energy reform near the Victory Monument yesterday.
Pol Col Prasopchoke said the judge advocate was investigating the case and collecting evidence.
Initially, the group was considered violating the martial law and an order of the National Council for Peace and Order that banned a political gathering of more than five people.
If the military does not file any additional charges, the Mr Veera and his group will be released within seven days of their detention.
If there are other criminal charges from the military, police will seek permission from the military court to extend their detention.