An 18-year-old girl and her minor brother were found murdered in their house here, police said Thursday.The bodies were spotted around 6.30 a.m. Thursday by their aunt on the first floor of the house located in Karawal Nagar area of east Delhi. The 10-year-old brother's body, with several wounds and a slash on the neck, was also recovered from the same room in which her nude body was found.The aunt who lives in the same house had come to wake up the siblings when she discovered the bodies.She informed their father who works in a courier company and was out of the house on some work. She also called the police.The police, who suspect the involvement of someone known to the siblings, have not ruled out the possibility of sexual assault on the girl."We have questioned neighbours and other relatives regarding the matter," a police officer said.