Lambton County OPP confirm that a one person has been found dead at the scene of an early morning fire south of Sarnia.

Police say emergency services responded to the 1700 block of St. Clair Parkway near Courtright around 2:30 a.m. Wednesday for a fire call.

Three males who were inside of the structure - which housed multiple residences - were transported to hospital, but no details have been released on their injuries.

OPP Const. Todd Monaghan says, "Later on during the investigation we discovered a deceased individual inside the structure."

The cause of death has not yet been determined and the investigation continues.

Monaghan adds, "We're working with the Ontario Fire Marshal to investigate the fire."

Police say any further information will only be released after additional investigations and next of kin notifications are completed.

But at the Tim Hortons in Corunna, the loss is already being felt. The person killed was reportedly scheduled to start a 7 a.m. shift at the restaurant, and co-workers were visibily saddened.

Management at the location would not allow employees to speak with the media.

St. Clair Parkway was closed between Courtright Line and Oil Springs Line for the police investigation for much of the morning but has since re-opened.