Is there documentation that he IS one of Jehovah's Witnesses? Unless I missed it, I do not find that in the article. Because he was holding a silver Bible does not mean that he is. Is it possible he might be a student, maybe even with a drug problem. He got his wanted attention. The wrong kind.
There are lots of factors to be considered. Each case is different. You need to talk to the elders in your congregation. They will make the decision . Talk it over with them. Rely on Jehovah to keep you on the right road. ( I answered this as if you were asking for yourself.)
This is a channel-bridge over the River Elbe and joins the former East and West Germany, as part of the unification project. It is located in the city of Magdeburg, near Berlin. The photo was taken on the day of inauguration. http://www.amusingplanet.com/2011/04/incredible-magdeburg-water-bridge-in.html