Police arrested a " potential suspect " Monday in the case of a nine-year-old girl who turned up safe two days after being violently abducted from her home .
Police arrested a " potential suspect " Monday in the abduction of a 9-year-old who was found safe after two days , the police chief said .
After more than two years ' detention under the State Security Bureau , the four were found guilty of subversion in Beijing 's No. 1 Intermediate Court last Wednesday .