TWEED, Ont. -- With little daylight at their disposal and a deep freeze setting in late Thursday, investigators quickly scoured the wreckage of a deadly helicopter crash in eastern Ontario.

None of the four Hydro One employees on board the Aerospatiale AS350-B2 chopper survived the crash, which happened shortly before noon, police said.

Parts of the aircraft were scattered over a snow-covered field outside Tweed, north of Kingston.

While provincial police confirmed the four deaths, and said that next of kin had been notified, the names of the victims were not released.

Darkness and a cold front that saw wind chill temperatures drop to near minus 30 eventually forced investigators to wait until first light on Friday to continue their probe into why the helicopter went down.

"We will document the scene, photograph the scene, gather as much information at the scene as we can," Transportation Safety Board investigator Peter Rowntree said as Ontario Provincial Police cordoned off the crash site for the night.

"At some point the wreckage will be removed to another facility so we can examine it in a warmer climate."

Crews had been ferried by helicopter in and out of the area for weeks as they worked on hydro lines strung on the towers that cross the property, said Kim Clayton, who lives near the crash site and grew used to hearing choppers fly back and forth.

Clayton said there was no indication of any trouble until a loud crash shook the house. She scrambled to a window, where she said she saw part of the chopper in the trees that surround an open field. Other hydro crew members were running around, yelling that a helicopter had crashed and to call 911, she said.

"My heart started pounding in my chest," said Clayton, 45, who moved onto the property just six weeks ago. "I was in panic mode."

Initially Clayton didn't think the situation was that bad but then she said she feared for the worst when she saw ambulances turn away without transporting any of the chopper's crew.

"I then said to myself, 'They're not coming out of this'."

The helicopter was apparently heading for a landing, Clayton said, adding she was relieved it didn't hit anyone on the ground or her horses, which were on the other side of the field.

Clayton, whose husband was away and children in school, said she choked up when the orange tape started going up and she realized just how bad it was.

"They have families, it's almost Christmas time," Clayton said. "I still can't believe four guys died on this property today and it's sad."

The Tweed fire department and several provincial police cruisers responded to the crash but there was little they could do. Ontario's air ambulance service was also called to the scene but left without loading any casualties.

In a statement, Hydro One expressed its condolences to the victims' families.

"We are deeply saddened to confirm that an incident involving one of our helicopter aircraft occurred in the Tweed area and has resulted in four fatalities," Hydro One said in a statement.

The utility also said it would do what it could to help employees and their families affected by the tragedy.

Prime Minister Justin Trudeau also expressed his sympathies.

"Tragic news from eastern Ontario today," Trudeau tweeted. "My deepest condolences to the loved ones of those killed in the helicopter crash near Tweed."

Rowntree said investigators would be looking at a wide range of factors to determine a possible cause of the crash, including photographic evidence of the wreckage.

"We'll also be looking at pilot records, training records for the pilot, aircraft maintenance records, aircraft history," he said.

"All that stuff we'll be looking at including weather at the time, and just looking at all the environmental factors to see if anything played a factor in what we're seeing here."

The single-engine AS350 is a utility helicopter often used for corporate purposes and by police.

In July 2007, the same model clipped a guy wire in northern Ontario and crashed, seriously injuring a Hydro One worker and the pilot. And in January 2015, an AS350 crashed in Saskatchewan during hydro cable stringing, seriously injuring the pilot. In both cases, pilot error was to blame.

Statement from Hydro One regarding employee fatalities in eastern Ontario:

We are deeply saddened to confirm that an incident involving one of our helicopter aircraft occurred in the Tweed area and has resulted in four fatalities. Emergency services are on-site and we have notified all the appropriate oversight organizations. Names will not be releases as next of kin are being notified.

Our thoughts and prayers are with their families at this difficult time. During this grieving process, we will do everything we can to assist our employees and their families who have been affected in any way, by providing counseling and support.

The safety of our employees is paramount and Hydro One together with appropriate safety agencies that have been dispatched will investigate the incident.

We will provide up-dates as information is confirmed.