A man has been arrested for murdering a Delhi University student following an altercation, police said on Thursday.The accused, identified as Ishtiaq Ali, 25, a resident of Uttam Nagar in west Delhi, was arrested after long investigation, police said."Ishtiaq Ali works as a sampling manager for various export houses and is an ex-student of a fashion institute. He confessed to killing Ayush Nautiyal, a B.com Honours student of a South Campus college after an altercation," said Joint Commissioner of Police Ajay Chaudhary.The incident occurred on March 22 and Ali, after killing Nautiyal, pretended that the latter had been kidnapped and sent a message, from the deceased's mobile, to his father demanding ransom of Rs 50 lakh to release him, he said.While Ali sent the message to mislead the police, Nautiyal's father approached police and a case was registered, he added."After Nautiyal's phone was switched off, Ali started using Whatsapp messages. He on March 26 sent message to deliver ransom amount near Uttam Nagar but did not come to collect the money."Nautiyal's body was recovered from a drain in Dwarka Sector 13. Ali was arrested with the help of technical surveillance and CCTV footage collected from various locations," said Chaudhary."Ali told police he disposed off the body the next day with the help of a friend. The vehicle used to dispose off the body has also been recovered. A manhunt is on to nab his friend," he added.