Suspect allegedly stole 21 pairs of the victim's underwear
Prior to the incident, the girl exited a shopping mall by bicycle
Over a 30-minute period, the woman attempted to fend off the suspect and screamed for help
Victim had vomited blood, police said
Suspect said of one victim, 'She signed a pledge to be a sex slave'
As of Monday, police had not found the murder weapon
No murder weapon has been found
Security camera footage shot near the bar showed the suspect with his arm around the woman as he escorted her into a taxi
Suspect used his smartphone to take nude photographs of the girl while she changed clothes
Suspect said, 'She did not dislike the act'