Where are China's missing human rights lawyers?

Two months ago China launched what appeared to be an orchestrated campaign, when more than 280 human rights lawyers and activists - along with their associates - were summoned, detained or just disappeared.

At least 29 of them are believed still to be in custody including Li Heping, one of China's best known civil rights attorneys.

The BBC's John Sudworth has been to meet his wife, Wang Qiaoling.