Pol Gen Somyos said the man, identified as Anont Klinkaew, a native of Samut Sakhon, was a leader of the security guards for PDRC protesters at the Chaeng Wattana government offices complex.
Mr Anont faces three charges.
In the first case, he and some other guards allegedly threatened a police officer on security duty at a petrol station on Chaeng Wattana road with guns and stole his handgun. This allegedly happened on April 22.
In the second case, on April 24, Mr Anont and other guards allegedly assaulted Col Vitvas Wattanakul, an officer attached to the Royal Thai Armed Forces Command, when he removed traffic cones blocking Soi 7 inside the government offices complex so he could return home.
In the third case, Mr Anont allegedly assaulted a police officer who was on the way to a meeting at the police club.
The man fled after warrants were issued for his arrest.
Metropolitan and Region 9 Provincial police learned that Mr Anont had been moving from one hiding places the next.
He was finally arrested yesterday on Thungsong - Nakhon Si Thammarat road in Ron Phibun district of Nakhon Si Thammarat.