A Delhi youth allegedly stabbed to death a 19-year-old man who had allegedly molested his sister in the Ambedkar Nagar area of Delhi on Saturday, the police said. The incident is reported to have taken place in South Delhi at around 10:30 am. The police said that the family of the victim tried to save the 19-year-old but was frightened by the accused. Right after stabbing his friend, the accused managed to escape even as the family raised an alarm. No complaint, however, has been filed by the girl or her family in relation to the alleged molestation..