GREENVILLE, Pa. - Mercer county District Attorney Peter Acker has closed his investigation into a triple fatal fire that killed a woman and her two children in late March. 

While the actual cause of the fire at 411 S. Main St. in Greenville on March 31 remains under investigation, the fire itself, which started in the rear of the house, has not been believed to be suspicious. 

Diana Mayes-Britton, 35,  and her two children, Johnathan and Olivia Mayes, 11,  died in the fire .

Acker's investigation had centered on a door on the second floor of the home which had been screwed shut, which prevented some of the people inside the house from escaping the fire. 

The home used to be owned by MCAR, which is an organization for the developmentally disabled. Having that door screwed shut during that time would have been potentially criminal, however there is no similar  restriction under the fire code if the house is owned and occupied as a primary residence. 

Timothy Britton, the husband of Mayes-Britton and stepfather to the children, told Acker he had placed the screws in the door after being asked to do so by his wife in order to stop anyone from coming in or out that door. 

Britton had also been in the house at the time of the fire, along with another child, who were both able to get out of a second story window. Britton believed the others were behind him at the time, but they were unable to find their way out through the smoke. Britton was taken by helicopter to a hospital for treatment. 

Acker said Britton has been completely cooperative with all aspects of the investigation and called it a tragedy.