A Shetland man went on trial at the High Court in Aberdeen on Monday accused of murdering his eight-month-old daughter by setting the family home on fire.
Billy Middleton, 32, is alleged to have wilfully set fire to curtains and clothes at the house in Brae.
It is claimed he murdered his baby daughter Annalise Middleton and attempted to murder two other children, aged six and three.
Middleton is further accused of sexually assaulting a woman while she was pregnant on various dates between April and September 2008 at a different address on the island.
However, he has lodged the special defence of consent and denies the assault allegation.
The jury were shown photographs taken of the family home after the blaze at 1 Burgadale, Brae.
The court heard that Middleton was rescued from the house during the fire on September 20 last year but his baby daughter Annalise was pronounced dead at the scene.
Independent fire investigator Stuart Mortimore said an investigation found that two separate fires had been started “deliberately” in the hall and ground floor bedroom.
He said: “The hall had been subjected to a relatively sustained fire. The only evidence of fire damage was under the stairs.”
He ruled out the hall fire sparking the blaze in the bedroom. And he claimed the possibility of electrical items causing the fire was “extremely remote”.
He said the bottom of the bedroom curtains had been destroyed which was consistent with fire being ignited and set against the curtain.
His investigations also found that fire spreading from the hallway would have caused damage to the ceiling of the room.
However, the 55-year-old said: “Mr Middleton was reportedly found on the bed in the bedroom. Neither he nor his clothes exhibited heat damage.”
Mr Mortimore said that a dead cat was found in one of the upstairs bedrooms during the investigation.
He told the court the local authority owned house had suffered extensive fire damage, particularly on the ground floor.
He said: “When two fires are started at the same time, the only explanation is that the fires were started deliberately.
“These fires are separate and distinct. Deliberate ignition is the only likely cause for these fires.”
Advocate depute Jock Thomson asked: “Both fires in your conclusion were deliberately set?”
Mr Mortimore replied: “Yes.”
Earlier, police photographer Vicki Paterson told the jury she had been called to the house following the fire.
The court was shown photos of blackened walls and destroyed doors inside the property.
A baby’s highchair was seen in the kitchen and children’s toys strewn across the floors of the bedrooms.
Middleton denies all the charges.
The trial continues.