Russian news media says remains of bomber to be examined . The station likely was packed with holiday travelers . Russian police say preliminary information points to a female suicide bomber . Video appears to show explosion inside the main entrance to the station . Bomber reportedly was approaching metal detector when explosion occurred .
Russian news media says remains of bomber to be examined . Russian police say preliminary information points to a female suicide bomber . Video appears to show explosion inside the main entrance to the station . Bomber reportedly was approaching metal detector when explosion occurred .