The bombs were shot with m79 grenade launchers, they were not placed on silom road. With so many high rise and apartment buildings, it would be hard to see where it was shot from, especially when fired at night. Even though there are police around, its not hard to sneak weapons in, the police only check pickup trucks and cars with red shirts, they don't check passenger cars. I could bring in weapons just as easily as you could.
I have a question: Where can people buy m79 grenade launchers? I mean, can you get then at Tesco? No, of course not. These grenade launchers are onwed by the Thai army, so maybe it was the army who exploded them. That means that the army too are gainst Abhisit. Does this man have any friends?