An email from a reader:

Sombat Boon-ngarmanong veteran pro-democracy activist has been arrested by police for organising peaceful Red Shirt activities in Bangkok. Sombat organised the first anti-coup protest in 2006 and is the organiser of Red Sunday, when people wear red shirts in cafes and shopping malls in resistance to the bloody repression of the Abhisit junta. Sombat was arrested while tying a red ribbon at Rajprasong… He comes before a judge on Friday.

Some further details here.