Firefighters at the scene in Boyle, Co. Roscommonirishtimes.com

Irish hearts have been moved by the plight of a family who lost a five year-old girl in what is believed to have been an arson attack.

The girl’s mother, Teresa Keane, gave birth to twin girls just two days before she lost her five-year-old daughter Marie Connolly.

Now Gardai believe an accelerant thrown through the letterbox of the front door may have started the blaze that claimed Marie’s life.

Marie Connolly died when her home in Boyle, Co. Roscommon, went up “like an inferno” according to firefighters.

Her father, Richard Connolly, suffered a broken back when he jumped out of a top-floor window with her sisters, eight-years-old Lauren and six-year-old Naomi, and saved their lives.

Marie’s mother was Richard Connolly’s former partner. While she was in hospital having twins, Connolly was minding their other three daughters.

Around 20 firefighters struggled to access rooms upstairs in the two-floor house because part of the floor, as well as the ceiling, had collapsed.

Naomi and Lauren were in the back bedroom upstairs when the fire broke out. It is not clear where Marie was.

Her body was taken from the house on Monday evening for a postmortem examination by Deputy State Pathologist Khalid Jabbar.

Forensic experts from the technical bureau at Garda headquarters in Dublin were called in to help with inquiries.

A heart-broken Teresa Keane visited the shell of her family's home on Monday to place a tribute to her daughter. She told the Irish Independent, "”I don't know what to say.”

Local people were horrified that Gardai suspected arson. They expressed disbelief that the fire might have been started deliberately.

Neighbor Frances Woods said the community was heartbroken. “She was a very happy little child, the poor little pet,” she said. “Her poor mother had twin girls on Saturday and the father brought them down to see the babies and they were all very excited.”

Surviving sisters Naomi and Lauren were treated for smoke inhalation. Their injuries were not serious.