The aircraft took off Wednesday from the city of Lensk, more than 1,000 kilometers east of the republic's capital Yakutsk, at about 6 p.m. local time, or noon in Moscow, according to an Investigative Committee statement published online Thursday.
More than four hours later, remains of the Eurocopter AS-350 helicopter were found from overhead by emergency personnel about four kilometers from its point of takeoff.
On Thursday morning, the bodies of three people who were aboard the aircraft were found, a UTair spokesperson told RIA-Novosti. The helicopter had a pilot, a mechanic and two passengers on board.
The rescue operation is ongoing, the Investigative Committee statement said.
The pilot steering the chopper, Vasily Gordeichuk, was experienced, with 5,091 hours of flight time under his belt, the spokesperson said.
Investigators have opened an inquiry into the accident.