New Delhi, Aug. 9 -- Delhi Police on Thursday arrested a 19-year-old man who allegedly kidnapped and killed his neighbour's eight-year-old son in outer Delhi's Kirari neighbourhood, and days after the murder demanded a ransom of Rs.25 lakh, the police said. The man, identified only as Gautam, killed the boy on July 23 pushing him into a drain, the police said. He wanted to use the ransom to pay for a vocational course at a private institute where he thought he would get placed in a decent job, they said....