The whereabouts of Mi Chongbiao and his wife are unknown.
Officials in the Chinese province say there is 'no evidence' to support suspicions over the death of a dissident's father.
The letter to President Xi Jinping garners more than 1,000 signatures.
Dozens of campaigners launch a probe into the 'suicide' of the father of a prominent dissident.
A Germany-based ethnic Mongolian dissident says the destruction of traditional grazing lands is at the heart of ethnic conflict in the region.
A Hubei-based rights group says tactics used against those who criticize the regime are getting harsher and more inhumane.
A woman has her wrist broken after she argues with officials trying to detain a fellow petitioner.