Chandigarh, Oct. 3 -- A school friend allegedly introduced the teenager accused of killing his father, a head constable with the UT Police, to an illegal arms dealer in Haridwar, police said, adding that the friend has been arrested. Identified as Lakshya, 20, of Ramdarbar, he was arrested with a country-made pistol on Thursday night. This is the third arrest in case. Police said Lakshya and the main accused, Armaan Singh, had studied at the same private school in Sector 45. The pistol recovered from Lakshya's possession was of a make similar to the one allegedly used by Armaan to shoot dead head constable Nitin Singh on September 25. He was produced in court and sent to judicial custody. According to police officials in the know of the matter, Armaan and Lakshya had travelled to Haridwar together in August, where Armaan allegedly got in touch with weapons dealer Mohammad Shaheen of Haridwar, Uttarakhand. About 10 days before the murder, Armaan allegedly returned toHaridwar alone to purchase the pistol. Police said they have closed-circuit television (CCTV) camera evidence showing Armaan and Lakshya travelling to Haridwar. They added that Lakshya was a drug addict, and like Armaan, unemployed too. Armaan was arrested on the day of the crime, while Shaheen was arrested three days later. Both were initially sent to police custody, which ended on Friday following which the court sent them to judicial custody. Police said Armaan had been studious during his school years. In fact, his family had encouraged him to prepare for the National Eligibility-cum-Entrance Test (NEET), but the draw of a luxurious life led him astray. According to the police, Armaan was eyeing the agricultural property owned by his father in Khatauli village, Panchkula. The family had also recently purchased a house in Zirakpur. Police allege that Armaan wanted to start a second-hand automobile business and had sought Rs.10 lakh from his father for the venture but the latter asked him to wait. Police said this led to resentment, and Armaan conspired to kill his father and mother to acquire the properties and live a luxurious life with the money....