ST. PARIS, Ohio -- Authorities in Champaign County said no criminal charges will be filed as a result of their investigation of a fire that left four children dead.

The fire started in a mobile home in St. Paris on March 21. Two adults and an infant daughter were able to escape.

Cassie Karg, Breonna Snelling, Patrick Snelling and Nathan Skaggs died in the blaze.

Prosecutor Nick Selvaggio said the evidence wasn't clear enough for his office to pursue criminal charges.

Selvaggio said, "When you have a tragic event people want answers. We did all we could to provide the knowledge of how and why it happened. But in this case we couldn't get an answer."

State investigators and a forensic engineer determined that the fire started in the corner of the living room.

They believe either a heater, an extension cord, or an electrical wire run along the floor to power the heater, started it all. But they couldn't determine which one.

Investigators said the home did have electrical problems, but determined they did not cause the blaze.

Selvaggio said relatives of the victims were disappointed to hear his results as were many of their neighbors. Neighbor Tracey Jones said, "Nobody can tell you who done it or what happened? It's very unfair."

Neighbor Deborah Collette said, "I felt devastated because there has to be some reason."

Champaign County spent $15,000 over the past six months investigating the deadly fire.