INDIANAPOLIS (AP) — Survivors of a deadly Indianapolis explosion are looking for answers as they try to move forward with their lives.

Some residents say they are frustrated by the pace of the investigation into the blast.

Investigators are focusing on natural gas-fueled appliances as they search for the cause of Saturday's explosion. The blast killed two people, leveled two homes and left dozens more uninhabitable.

Indianapolis Homeland Security Director Gary Coons said Tuesday that his "investigators believe natural gas is involved" and were "recovering the appliances from destroyed homes to help determine the cause." He made the announcement after the National Transportation Safety Board said investigators had found no leaks in the gas main or pipes leading into the house that exploded.