A student of the Delhi Technological University has been arrested for allegedly killing a 31-year-old teacher at his tuition centre in northwest Delhi's Mahendra Park earlier this week, police said on Friday.
Aakash, 21, a resident of Jahangirpuri, was arrested on Thursday night from his residence for allegedly killing Ankit Sagar, they added.
Sagar's family members had claimed he was in a relationship with a girl from another community and her brother had killed him.
Deputy Commissioner of Police (Northwest) Aslam Khan said all the current and previous students of the tuition centre were thoroughly interrogated. The relatives and friends of the victim were also examined.
"CCTV footage of the area was scanned, and we got the picture of the accused. Aakash was found and arrested from his house in Jahangirpuri," the officer said.
During interrogation, he disclosed that he was in a relationship with a woman, who was earlier in a relationship with Sagar.
Even after their breakup, Sagar would talk to her and did not want to leave her. Aakash wanted to marry the girl and was "over possessive" about her, he said, adding the accused thought Sagar would not stop and continue to harass her.
On Holi, Aakash went to Baghpat, Uttar Pradesh, where he bought a country-made pistol. Since then, he had been planning to kill Sagar.
"In the early hours of Monday, Aakash went to the coaching institute wearing a pollution mask and a cap to conceal his identity. When Sagar entered the tuition centre, he shot in the head from back," said the DCP.
Aakash is a fourth-year student of the Delhi Technological University.
Sagar's brother used to teach Aakash and the woman was Sagar's student.
A country-made pistol, a bag, a mask and a cap, all used in the crime, were seized from his possession.