A humiliated girl student committed suicide here after a teacher barged into her house demanding unpaid school fees, police said on Thursday.The father of the 16-year-old Class 9 student at the DSP Higher Secondary School in Ghaziabad could not pay her school fees. He then shifted the daughter to another school. On Wednesday night, the DSP School teacher along with three accomplices barged into the student's house and demanded Rs 11,000 in outstanding fees from her father. The father, Ratan Singh, a security guard, sought some time to pay up. After a heated argument, the teacher summoned the police who took the father away for questioning. When the father was in police custody, the student, who was alone in the house, hanged herself from a window with her scarf. The police have registered a case of abetment to suicide against four persons, all teachers and staff of the DSP School, police officer Anish Gautam said.