NOVOSIBIRSK, January 15 (RIA Novosti) - Investigators have completed all the necessary procedures at the site of last week's Mi-171 helicopter crash in Altai, south Siberia, a spokeswoman for the local transport investigation department said on Thursday.

"An investigation team has completed its work at the crash site," Tatyana Dubinyuk said.

Last Friday's crash killed seven people, including the Russian president's envoy to the State Duma, Alexander Kosopkin and a regional environmental official, Viktor Kaymin, who were part of a hunting trip to the mountainous area. Four people survived the crash.

The government of the Republic of Altai earlier confirmed the helicopter passenger were hunting animals and had all the necessary licenses, amid reports that the party had killed an endangered species of mountain sheep.

In a photograph from the crash site, posted on an Altai Internet site, the carcasses of Altai mountain sheep, or argali, are clearly visible among the helicopter wreckage. There are reported to be just 200 Altai mountain sheep remaining in Russia.

According to some reports, the crash may have been caused when the helicopter captain descended to a minimum altitude either to pick up the carcass of a shot mountain goat, or to take a better aim.

WWF Russia issued a statement confirming that the slain animals were mountain sheep and demanded an investigation into the incident.

A spokesman for the Russian nature resources ministry, Nikolai Gudkov, said hunting rare animals is allowed only in "exceptional cases" such as preserving the population and preventing the spread of disease. It requires a special license from the environmental ministry and is applied mainly to polar bears.

"I've never heard about a case when such a license was issued for mountain sheep. It mainly concerns polar bears who pose a threat to humans when in populated areas," Gudkov said.

The second pilot, Maxim Kolbin, said in an interview with respected Russian daily Izvestia that one of the helicopter's twin engines had stopped as the aircraft hovered in the air at low altitude.

However, the International Aviation Committee dismissed reports about an engine malfunction citing data from the helicopter's black boxes.

"A preliminary analysis showed that the helicopter's engines were functioning," the committee said in a statement.