Investigators are looking for the cause of a fire that destroyed one home and damaged another overnight in southwest Calgary.

Fire crews were called just after midnight on Saturday morning to a fire at Roxboro Road S.W. and Third Street S.W. They haven't identified a cause yet but say the fire department had been to one of the homes earlier Friday evening.

"We were there at 10 p.m. for an investigation of a smoke complaint out of a fire pit," said battalion chief Larry Fisher. "A neighbour phoned in complaining about a lot of smoke, so the fellow had a fire pit on the deck in the back."

When crews arrived Saturday morning, they found two homes on fire.

While no one was seriously injured, fire crews say there could have been dangerous complications.

A natural gas line ruptured as a result of the heat, which could have led to an explosion.

It had to be shut down by Atco personnel.

As well, a live electrical wire fell into the backyard of the home and crews had to wait for Enmax to disconnect the power feed.

The owner of the home where the fire apparently started is an 89-year-old man who returned Saturday shortly before noon to search for his cat, Ozzy.