Guwahati/Jorhat, Jan. 29: A worried Assam forest minister Rakibul Hussain today requested chief minister Tarun Gogoi to press for a CBI inquiry into the current spate of rhino killings in the state.

This follows the killing of a yet another rhino, the fifth in the state this year, at the Parku Pahar range in Karbi Anglong, close to the Bagori range of Kaziranga National Park, last night.

Hussain also wants the chief minister to move the home ministry to expedite the allotment of AK-series rifles to forest guards in Assam. The proposal has been pending with the Centre since last year.

"The chief minister had written earlier to the CBI but the agency did not take up the case. I requested him today to pursue the matter," Hussain told The Telegraph. "We need to find out why poaching continues despite increased patrolling."

The latest incident comes within 24 hours of a rhino being killed at the Burapahar range of Kaziranga National Park on Sunday night. Both the incidents occurred within a kilometre of each other.

In the latest case, poacher Bikhou Engti was arrested from Silim Khowa Gaon in Karbi Anglong after sniffer dogs were pressed into service by the forest department to follow the trail. But people from the area broke open the lock-up at the Bagori range office today and released Engti.

Earlier, Dibyadhar Gogoi, divisional forest officer, eastern Assam wildlife division, Kaziranga National Park, said they were interrogating Engti and more arrests would be made based on his statement. Two cartridges of a .303 rifle, an axe, two gunny bags, and two machetes were recovered from the site of the incident.

According to Bagori range officer K. Deka, forest guards posted in the area had heard gunshots around 10.20 last night and returned fire. But they failed to get to the spot before the rhino's horn was removed. The carcass was located at 11 last night.

Amarendra Talukdar, ranger of Parku Pahar, said a combined team of Kaziranga National Park and Karbi Anglong district officials had arrived at the spot within minutes of the incident. But the shots had been fired from atop a hill and no trace could be found of the poachers, who fled with the horn.

Kaziranga National Park director N.K. Vasu, however, said such incidents were "one-off incidents" and that the national park was a success story. "The people living in the vicinity of the park are not involved in such incidents and because of the expansion of park area it will take time for people living in those areas to get involved in conservation efforts," Vasu said.

A second person, Sing Rongfar, has been arrested in connection with the killing of the rhino at the Burapahar range on Sunday night. He had been involved in the killing of three rhinos in 2007, a forest official said.

"He was arrested on the basis of information provided by another poacher who had been arrested earlier. The poacher had also revealed that two persons from Nagaland were involved in poaching," the official said.

The World Heritage Centre has asked Delhi to submit a "state of the conservation report" for Kaziranga, detailing steps taken to control poaching, a source said. "The report should be sent by first week of February so that it can be presented at the 37th meeting of the World Heritage Committee at Phnom Penh in June," the source added.