Billy Powers and wife, Donna, were found in their home in the city's southwest early Thursday.
Derek Puffer, who is 35, is charged with two counts of second-degree murder.
Staff-Sergeant Grant Miller says Puffer is Billy's stepson and Donna's son.
He says Puffer was living with the Powers at the time of their deaths.
Powers retired in October 2009 after almost 50 years in the sports broadcasting and communications business.
He worked mainly in radio and was also media co-ordinator for a time for the CFL Calgary Stampeders.
Police say they don't believe drugs or alcohol were factors in the couple's death.
"So the why in this is truly is the big question," Miller said.
"It absolutely is what our investigation is focused on. Unfortunately the other parts to this probably are as they seem and now our investigators are focused on why."
Police got involved in the investigation when a call came in early Thursday about a naked man standing on the side of the road.
"We've spoken with him and as a result of speaking with him, he is now charged with two counts of second-degree murder," Miller said.
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