Investigators are trying to reconstruct what happened, and help from the victims' family may help pinpoint that cause.

Even though the house is gone, what used to be there may answer some questions. The explosion completely leveled the house, but its floor plans may be able to tell what caused the destruction.

"We were able to get the first look as to how the home is laid out," said Steve Sapp of the Columbia Fire Department. "Because of the explosion and ensuing fire, we didn't know what the floor plan of the house was, what appliances were in the home, what appliances were electric versus natural gas."

These factors are important to know so investigators can pinpoint areas of the house where explosive material may have been a problem. The fire department has checked over the past weekend to make sure that no hot spots or fire has popped up from what's left of the house, but they said they don't have to worry about that because all the wet weather in the area recently.

While the fire department serves as the investigator, Ameren UE is helping in other ways.

"One of the things that we did was actually search our records to determine if we had any reports of a gas leak at that address, and we couldn't find anything." said Mike Cleary, of Ameren UE.

Ameren found no problems with the outside gas lines, but that doesn't mean a leak inside the house could have caused the explosion. Although natural gas may be the most probable cause, investigators want to rule out any other possibilities before they say they're sure. Some of the other causes could include explosives like gunpowder or old war relics. It is also unknown if the couple used oxygen tanks, which are highly explosive.