By Dennis Owen

WINFIELD, British Columbia (Reuters) - Former Alberta Premier Jim Prentice was one of four people killed in a plane crash in British Columbia, his family confirmed on Friday, as Canadians across the political spectrum paid tribute to his dedication to public service.

The Royal Canadian Mounted Police have not yet released names of the four people who died in the crash on Thursday night. Prentice's family said the other victims included the father-in-law of one of their daughters.

"Words cannot begin to express our profound shock and heartbreak," the statement from Prentice's family said.

Canada's Transportation Safety Board said it was investigating the wreckage of a downed Citation jet bound for Calgary, Alberta, when it crashed shortly after takeoff from Kelowna, British Columbia.

Police said they reached the scene shortly after midnight and found catastrophic damage.

Prior to becoming Alberta premier, Prentice held several portfolios in the Conservative government of Stephen Harper, including industry, aboriginal affairs and the environment.

Liberal Prime Minister Justin Trudeau noted Prentice was a highly respected and well-liked member of the House of Commons. Leaders of the federal New Democrats and Green Party both said he would be sorely missed.

"All of us in the Conservative family are ‎devastated today," said federal Conservative leader Rona Ambrose.

Conservative Member of Parliament Gerry Ritz, who served in the federal government with Prentice, remembered him as a politician who distinguished himself by his passion.

"The world's a sadder place," Ritz said. "He was one of the best aboriginal affairs ministers we've seen in this country. His never back up attitude and his passion set him apart."

After Prentice left federal politics in 2010, he joined Canadian Imperial Bank of Commerce, where he stayed until 2014. CIBC Chief Executive Officer Victor Dodig said he was "a great friend, colleague and Canadian."

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Prentice was leader of oil-rich Alberta for less than a year. His Progressive Conservative party lost to the left-leaning NDP party in May 2015.

Alberta Premier Rachel Notley, who lost her own politician father in a plane crash, called it an "unspeakable tragedy" and praised Prentice's commitment to public service.

Prentice's tenure as premier coincided with a dramatic slump in oil prices that slammed Canada's biggest crude-producing province.

Many Albertans blamed the incumbent Conservative government, which at that point had been in power for 44 years, for not building a bigger financial cushion during the boom years.

(Writing by Nia Williams in Calgary, additional reporting by Leah Schnurr in Ottawa, Jeffrey Hodgson in Toronto and Rod Nickel in Winnipeg; editing by Chizu Nomiyama and David Gregorio)