Calgary-based utility AltaGas Ltd. (ALA.TO) is appointing Randy Crawford as CEO four months after the sudden resignation of ex-CEO David Harris following an unspecified "complaint" to its board.

In a news release, it says Crawford will take the reins on Dec. 10 from interim co-CEOs David Cornhill and Phillip Knoll, its chairman and a member of the board, respectively.

AltaGas says Crawford has 30 years of experience in the natural gas industry and was most recently the president of midstream and commercial with EQT Corp., a U.S. gas company, where he led a growth strategy in the Marcellus natural gas fields in the northeastern U.S.

It says the new CEO will be asked to strengthen AltaGas' financial position, as well as focus on growth and new opportunities in its gas and U.S. utilities segments.

The company said in July the complaint regarding Harris was not related to AltaGas' strategy, operations or financial reporting, but hasn't explained what it was related to or who made the complaint, nor has it given any detail of a review of the complaint it said it would undertake.

Harris, who had been with AltaGas since 2010 and its top executive since April 2016, oversaw the company's $6-billion deal to buy Washington, D.C.-based energy utility company WGL Holdings, Inc., which closed three weeks before his departure.