The Criminal Court on Tuesday dismissed a petition filed by the head of a student activist group seeking to have Sunday’s arrest of Thammasat University student Thanet Anantawong ruled unlawful.
In the petition lodged with the court on Monday, Democracy Studies group leader Sirawith "Ja New" Seritiwat claimed the arrest and detention of Mr Thanet had violated Section 90 of the Criminal Procedure Code as the plainclothes officers who took the 25-year-old while he was at Sirindhorn Hospital in Prawet district, did not present an arrest warrant and did not identify themselves.
The court said the information Mr Sirawith used to back his plea was only hearsay from Mr Thanet and it could not confirm whether the arrest occurred as claimed.
The petition itself also said Mr Thanet had acknowledged that he was wanted on an arrest warrant and wanted to surrender to face the charges.
The court ruled the petition had no sufficient grounds to proceed further.
Mr Sirawith said he would resubmit his request with more evidence from witnesses tomorrow afternoon.
Human Rights Watch claimed in a statement on Tuesday that Mr Thanet was taken from the hospital while he awaited an operation.
"Thailand's junta has reached a new level of ruthlessness by snatching an activist from his hospital bed," said Brad Adams, Asia Director at Human Rights Watch.
But National Council for Peace and Order spokesman Col Winthai Suvaree said Mr Thanet's medical treatment had been completed by the time he was detained.
"He was detained after his medical check-up was done and he was paying for his hospital fees," Col Winthai told Reuters.
"In any case, as we were concerned about the suspect's health, we invited doctors to check him and found that he did not have a serious medical condition."
Mr Thanet would receive adequate medical attention while in the care of the authorities, he added.