
Police took Ekkalak Phaenoi, who is accused of assassinating a Cambodian opposition politician in Bangkok, to the Criminal Court on Monday and applied to extend his detention.
Mr Ekkalak was escorted amid maximum security from Chana Songkhram police station to the court, where police applied for a first 12-day detention period after his police custody reached its limit.
The suspect refused to answer reporters' questions and went directly into the van that took him to the court.
Mr Ekkalak, 41, faces several related charges including shooting dead Lim Kimya, 73, a former Cambodian opposition lawmaker, in front of Wat Bowonniwet Vihara near Khao San Road in Bangkok last Tuesday.
He fled across the border and was arrested in Battambang in Cambodia the next day and extradited to Thailand.
Thai investigators believe he did not act alone and at least two other Cambodians could be linked to the assassination.
On Sunday, Mr Ekkalak refused to take part in a police crime re-enactment because of fears for his safety.
Pol Col Ekkaphob Tanprayoon, deputy commander of Metropolitan Police Bureau Region 1, said police instead showed him the street security camera footage of the crime so he could confirm his statement. He has allegedly admitted to the murder.
The motive remains unknown, but Cambodian politics is believed the most likely. Lim's party was disbanded by a Cambodian court.
According to Thai media reports, Mr Ekkalak has told police he is too scared to name the mastermind.