Parit "Penguin" Chiwarak, a co-leader of the Ratsadon group, was detained on Sunday when he showed up at the Royal Thai Police (RTP) Office, two days before a key rally is staged at the Ratchaprasong intersection.
Police also detained 14 suspects in connection with violence, including arson, during the protest on Saturday.
Mr Parit reported to RTP headquarters after being summonsed on Aug 2 over his role behind the graffiti that appeared outside the Region 1 office of the Border Police Bureau in Pathum Thani. He went there to lobby police to release protest leaders being held in custody.
On arrival, police presented him with an arrest warrant issued by the Thanyaburi court. It also issued a warrant for Natchanon Pairoj, another co-leader of the Ratsadon group who was also required to report.
Mr Parit told supporters who gathered there to continue the fight without him and join the rally at the Ratchaprasong intersection tomorrow.
Meanwhile, police released details of the 14 suspects detained in connection with Saturday's violence.
Four were charged with arson and injuring police, while the others face charges for being involved in illegal and criminal activities, said Pol Maj Gen Piya Tawichai, deputy commissioner and spokesman for the Metropolitan Police Bureau (MPB). He said three crowd control police were injured during the weekend's clashes with protesters at Din Daeng intersection.
One of the injured three was still in intensive care at Police General Hospital after he was shot in the back of his neck, said Pol Maj Gen Piya.
Pol Lt Col Barami Wong-inta, a police investigator with Phaya Thai station, said a police detention truck was torched and a police booth was badly damaged during Saturday's resumption of clashes.
The Free Youth group on Saturday posted on its Instagram a message reading: "The people have fought back burning up a police car!"
After criticism over the riot, it edited the post later to say: "It remains unknown who burned it."