The cause of a car fire that left two Akron children dead will likely remain unsolved.

Investigators from the Akron fire and police departments think one of the three children in the back of the car was likely playing with matches or a lighter. But investigators have been unable -- based on interviews and evidence -- to prove that was what caused the Oct. 29 fire.

``We have ideas about what happened, but it is all speculation,'' said Akron Fire Lt. Dennis Nelson.

Akron Police Sgt. Kevin Culver said yesterday that police will not file charges against Tara James, the boys' mother, who left her three young sons in the back of her car while she ran into a friend's house. Culver said James was in the Vincent Street house for about five minutes when the car holding her children burst into flames.

One-year-old Tajzon James was rescued from the burning car, but 2-year-old Robert and 4-year-old Sharif James died from smoke inhalation. Bystanders tried to save the other two boys, but the fire was too far along.

``This is a terrible tragedy for her and her family,'' Culver said of Tara James.

Investigators said Tara James smokes cigarettes, but she wasn't sure if one of her children could have gotten a lighter or matches.

The three boys were dressed in Halloween costumes, prepared to go to a holiday party with their mother.

Nelson said the costumes were store bought. He does not think the garments contributed to the boys' deaths. He said the inside of the car was filled with synthetic materials that were all highly flammable and made the fire burn fast and extremely hot.

``It wouldn't have mattered what they were wearing,'' he said.

Investigators determined that the car was not running at the time of the fire and the blaze was not caused by any problems with the vehicle.