KELOWNA, B.C. -- Hours of painstaking work lies ahead as Transportation Safety Board crews wrap up their investigation at the scene of a fatal plane crash in British Columbia that killed former Alberta premier Jim Prentice and three other men.

Investigators now move to the lab after collecting all the required information from the crash site, about 10 kilometres northeast of the Kelowna airport in B.C.'s Okanagan, the safety board said on Wednesday.

Wreckage of the Cessna Citation will be removed from the wooded area by helicopter and taken to a warehouse for further analysis.

In a news release, the board said some of the upcoming work includes reviewing RCMP drone footage of the crash scene, examining the plane's instruments, sending selected wreckage to its lab in Ottawa, and evaluating plane maintenance and pilot records.

Investigators will also create simulations and reconstruct events to learn more about the sequence of events leading up to the crash.

"We will be thorough in our analysis of the data we have collected, and will continue to gather information as the investigation progresses", said TSB investigator-in-charge Beverley Harvey in the release.

If, during the ongoing probe, safety deficiencies are found that require immediate attention, Transport Canada and the industry will be informed, and the details will also be released to the public, the board said.

The Cessna Citation crashed and burned last Thursday night and investigators have reported it could take as long as a year to determine a cause.

The board described the investigation as particularly challenging, partly because the aircraft did not carry flight-data or cockpit-voice recorders.

No distress signal was issued before the plane vanished from radar just minutes after takeoff from Kelowna on a flight to Springbank airport, near Calgary.

Also killed in the crash were pilot Jim Kruk, a retired RCMP officer, Calgary businessman Sheldon Reid and optometrist Ken Gellatly, the father-in-law of one of Prentice's three daughters.

The Alberta government said Wednesday that a state memorial will be held for Prentice in Calgary a week from Friday.

A statement from Premier Rachel Notley's office says the service at the Southern Alberta Jubilee Auditorium will be open to the public.