Calgary police are releasing new information about the driver of pickup truck they hope will help in the homicide investigation of Don and Roxanne Carlson two years after their deaths.

Friends of the couple have also renewed their $25,000 reward for information that directly leads to arrests or convictions.

Their bodies were discovered by police in their southeast Calgary home in February 2014 for initial reports of a suspected carbon monoxide leak — that was later ruled out. 

When crews arrived, one of the individuals was dead while the other was in medical distress and died a short time later.

The cause of death has not been released.

"We're not going to let it drop. We're going to turn over every stone." said Insp. Steven Barlow.

Several leads being pursued

Sketches in Don and Roxanne Carlson homicide

One year after the homicide of Don and Roxanne Carlson, police released these sketches of men observed in the area at the time of the deaths. These men remain people of interest in the investigation and have yet to be identified. (Calgary Police Service)

Last year police released sketches of two men seen in the area and believed to be connected to the Carlson's death. They have yet to be identified.

Around that time investigators received more information about a newer silver or grey pickup truck seen in the area around the time of the crime.

Police have determined that truck was a rental used by a man with fake B.C. identification and credit cards.

It's not known whether this man had any involvement in the homicide — however, police are asking the public for help tracking him down.

"Somebody knows this person, and we're hoping that they'll come forward," said Insp. Barlow. "We're hoping, and actually begging the public to come forward and understand that we have two people that have been killed."

Tips can be submitted to the Homicide Unit directly athomicidetips@calgarypolice.ca or by phone at (403) 428-8877 or Crimestoppers