INDIANAPOLIS, Indiana- Investigators are trying to determine what set off a blast that killed two people and destroyed five homes.

The explosion was so powerful it was heard and felt for miles.

The houses at the epicenter of the blast are gone.

Dozens of other properties were damaged beyond repair.

Authorities estimate the cost will run into the millions of dollars.

Officials say there was no smell of gas before the explosion .

The two who were killed were husband and wife.

The woman was a teacher.

A congressman who represents the area says he's been told a bomb or meth lab have been ruled out as causes of the explosion.