Somyos Ketmanee, who was carrying scissors and alternately claimed to be both a well-connected army officer and a cousin of Prime Minister Yingluck Shinawatra, was arrested for damaging vehicles with fist-sized stones July 10 on the Sukhumvit Road between Sattahip and Rayong.
Police, unable to subdue the rock thrower, look on whilst civilians provide their own justice.
Police tried to subdue the suspect near mile marker 81, but Somyos fought back and broke away. At that point, victimized motorists and passersby set upon the man, beating him for several minutes before police could fend off the crowd.
About 10 cars were damaged in the rock barrage, but no one was injured.
Police suspected the man was agitated due to drug use or mental illness and arrested him for damaging property and causing traffic risks.