An off-duty Hong Kong police officer was arrested along with seven other people on Friday as they tried to put pro-democracy posters on a footbridge, police said. It's the first known case of a police officer being apprehended for supporting the massive demonstrations that have led to more than 6,500 arrests in the past seven months. The officer, 31, and the seven other people aged 14 to 61, were arrested at 3:00 am on Friday in Tuen Mun, a district in northwest Hong Kong.