Body of the boy revealed marks on his neck consistent with strangulation, police said
Suspect denies the allegations, telling police, 'I didn't do that kind of thing'
Prior to incident, suspect searched for women before spotting the girl out walking
Suspect told police, 'I thought about whether to stab a person or start a fire'
Injuries to the victim are not considered life-threatening, police said
Suspect told police, 'I wanted to stab her,'
Suspect told police, 'I did it to cover living expenses and rent'
Suspect told police he 'didn't know' he was in possession of illegal drugs
Father of victim said, 'The criminal who killed our daughter can never be forgiven'
The body, bent at the knees, was packed inside a 1-meter-long box, police said