A man accused of murdering eight people in a "carefully planned" house fire asked "did you see the way it went up?" moments after the attack, a court heard.
Shahid Mohammed, 37, is alleged to have been directly involved in the killing of five children and three adults in the blaze at the property on Osborne Road, Birkby, Huddersfield, 17 years ago.
Prosecutors say he conspired with several other men to use petrol bombs made from milk bottles in order to set the home alight following a bitter family row.
On Thursday, Leeds Crown Court heard the defendant and another man, Shaied Iqbal, had driven in the early hours of May 12 2002 towards the property, allegedly carrying petrol bombs in the back of the Nissan Micra they were travelling in.
Alistair MacDonald QC, prosecuting, said a witness had later seen the pair, and two other men, running away from the house wearing "cream or white latex gloves".
The prosecutor said that after getting back into the car, Iqbal was described as being "very happy and was smiling", and Mohammed said to him: "Did you see the way it went up?"
Jurors had previously been told that in a 2003 trial, Iqbal was convicted of eight counts of murder, while Nazar Hussain and Shakiel Shazad were both found guilty of eight counts of manslaughter in relation to the fire.
The court was told Mohammed did not stand trial at that time as he had skipped bail and fled to Pakistan, and only returned to the country last year following an extradition request by the UK Government in 2015.
Mr MacDonald said: "It is, as you know, part of the prosecution case that the reason he absconded and broke his bail was that he is guilty of the arson on Osborne Road and the murders of the family there."
The court heard it is believed the target of the attack had been Mohammed Ateeq-Ur-Rehman, known as Ateeq, who died in the fire along with his sister Nafeesa Aziz, 35, and her daughters Tayyaba Bootall, three, Rabiah Bootall, 10, Ateeqa Nawaz, five, Aneesa Nawaz, two, and six-month-old Najeebah Nawaz.
Their mother Zaib-un-Nisa, 54, died a week later in hospital after suffering head injuries as she jumped from the burning home, jurors heard.
The court heard Ateeq had allegedly been targeted because he had played an "active part" in maintaining a relationship between the defendant's sister, Shahida Younis, and her husband, Saud Pervez.
The prosecutor said: "The defendant and his family were deeply unhappy about that relationship.
"The prosecution say that this defendant was at the forefront of the disapproval of the relationship between his sister and Saud.
"He had a direct, close and persistent hatred of what had happened. Because it was his sister, it was highly personal so far as he was concerned.
"He threatened that he would kill anyone who helped Saud and his sister to further their relationship, and it is the prosecution case that he did just that to Ateeq, who he had discovered was a close friend, and supportive, of Saud."
Mr MacDonald said a fire expert, Dr Swan, had investigated the property following the blaze and found there were "two separate areas of origin" of the blaze, one in the lounge and one in the hallway.
Jurors heard petrol bombs made from milk bottles, with a rag on their necks, were thrown in through the double-glazed lounge window, while the hallway fire was caused by petrol being poured in through the letterbox and ignited.
Mr MacDonald said: "The prosecution say that this was a carefully planned attack on this house and that those who set these fires knew what they were doing, knew that the house was occupied and intended to cause really serious harm to the occupants of the house."
Mohammed denies eight counts of murder and a single count of conspiracy to commit arson with intent to endanger life.
His trial continues.