Denise Goldsmith, 29, was arrested on suspicion of manslaughter and child neglect but later released on police bail until early December.
It also emerged this week that Stuart Jenkins, the father of the boys who died, is currently on remand in prison having been charged with rape between July 27 and 30 this year.
A special hearing took place behind closed doors at Lewes Crown Court yesterday where he made an application for bail which was refused.
The developments this week have shocked people living in theShinewater area, where the tragedy occurred on Saturday afternoon.
The fire in the end-of-terrace house in Milfoil Drive led to the deaths of brothers Taylor Jenkins, five, and Lewis Jenkins, seven, both pupils at Shinewater Primary School.
Post morten examinations were carried out on Monday in London and police later stated that the boys had died as a result of the inhalation of fire fumes.
The cause of the blaze, which severely damaged the terraced house, is being investigated by East Sussex Fire and Rescue Service and Sussex Police detectives but it is not being treated as arson. No information has as yet been released about the cause of the fire, or where in the house it started.
Denise Goldsmith was taken to the DGH with minor injuries after the fire and paid a tearful visit to her burnt-out home on Sunday where she tried to enter but was held back by police.
People from a wide area have continued to lay flowers and tributes oustide the house which remains cordoned off and guarded by police.
The shock of the tragedy has been far-reaching.
Former Eastbourne resident and Anglican priest Father David Cloake, of Aylesbury, sent a message to the Herald saying, "This message comes with the prayers and best wishes of the people of Aylesbury.
"Everyone was shocked by the terrible news of the untimely deaths of the two boys. We will hold them and their families in our thoughts and prayers at this terrible time.
"I have family who live near the scene of the fire, and I myself grew up in Eastbourne, so this awful loss is felt more poignantly by me."
More than 1,200 people have visited a memorial website - http://two-little.gonetoosoon.org/memorial/ - to leave tributes to the 'little angels'.
Shinewater Primary School held a special assembly for pupils, one of whom, eight-year-old Nadeem Khusar, was best friends with Lewis and had invited him to his birthday party on the day after the fire.
There have been media reports that Taylor, said by headteacher John Greenwood to idolise his older brother, was found huddled with Lewis in the house but police said they could not confirm this.
Shinewater Community Church is holding a memorial service at the Community Centre in Milfoil Drive on Sunday at 10am to which all are invited. A book of remembrance for Taylor and Lewis will be opened at the same time.