An eight-year-old girl was allegedly sexually assaulted by her landlord's son here on Wednesday -- but her parents came to know about the assault only a day later when doctors told them about injury marks on private parts. The accused was arrested after two days, police said on Friday.According to the police, the victim (8) was residing with her parents in a rented accommodation in Maharajpur locality in Ghaziabad. On September 9, when the girl's parents were away at their respective jobs, their landlord's son Basant barged into the rented portion of the house. He dragged the girl inside the room and raped her. Facing resistance, the accused burnt her private parts with a lit cigarette, police said.When the girl complained of pain on Thursday, her parents took her to Hedgewar Hospital in east Delhi's Karkardooma area where the doctor noticed the injury marks on and around her private parts. Police registered the complaint on Friday."We have registered a criminal case against the accused under section 376 and protection of child from sexual offence Act. The culprit has been arrested," said Ajay Pal Sharma, Superintendent of Police, Ghaziabad City.