Chennai, July 10 (IANS) A week after a teenager was killed in a military residential campus here, a retired army officer was arrested Sunday after he confessed to the crime as he was irritated by the boy's trespassing, police said. He was remanded to 15 days judicial custody.

Lt. Col. (retd) K. Ramaraj, 58, had shot K. Dilshan from the balcony of his residence July 3 when the 13-year-old boy and his friends trespassed into the campus to pluck almonds. Dilshan was seriously wounded and succumbed to his injuries in a hospital.

Ramaraj, who has three sons serving in the army, was produced before a court here and remanded to 15 days' judicial custody.

Additional Director General of Police R. Sekar told reporters: "The initial suspicion was on somebody else. But the CB-CID (Crime Branch-Criminal Investigation Department) team ruled out that person and zeroed on Ramaraj."

He said physical verification, forensic tests, ballistic test reports and views of weapon experts led to Ramaraj's detention.

According to Sekar, the accused who retired from service three months ago had acquired a 0.30 calibre Springfield rifle in 2004 when he was posted in Jabalpur, Madhya Pradesh.

"The licence had expired and he had applied for renewal to police here which we came to know of during investigation," the police officer said.

The army officers here were not aware that Ramaraj was in possession of a rifle, Sekar added.

According to the CB-CID, extensive searches were carried out at the place of shooting and a bullet component was recovered and sent for ballistic tests to ascertain the type of weapon used.

Initially it was thought that three boys, including Dilshan, had entered the campus. But the probe established the presence of a fourth boy, who gave information about the probable involvement of Ramaraj.

D. Chandrabasu, superintendent of police with CB-CID told IANS: "Initially we suspected Lt. Col. Ajay S. Bharwal as he chased the boys first before going out of the campus."

"We learnt the boys came back again. It was then that the shootout happened," he added.

He said the retired army officer was not able to explain his presence and absence at the campus around the time the shootout happened.

According to police, Ramaraj had come out and inspected the spot where Dilshan fell down after the gun shot. He also went out in his car to dispose of the rifle and the remaining ammunition in the river.

Twelve probe teams were constituted to crack the case.

"On being interrogated, Ramaraj denied having committed the offence. When he was shown the gun licence submitted for renewal, he confessed," Sekar said.

Ramaraj said he had thrown the rifle and the bullets into the Cooum river here. The police recovered the rifle from the river while the bullets were still to be found. Sekar said the car used by Ramaraj for carrying the weapon was also seized.

According to CB-CID officials, Ramaraj was living with his wife here for the past two-and-a-half years.

"It was a very challenging case to crack. We feel happy that it has been cracked finally," Deputy Superintendent of Police Sonal V. Misra said.

Police said the army extended full cooperation in cracking the case.