Three men blew up a shop in Leicester in a £300,000 insurance scam, killing five people including a friend who knew too much, a court heard.
Firefighters spent hours tackling the major blaze that wiped out a Polish supermarket in Hinckley Road on February 25.
Prosecutors claim that Arkan Ali, Hawkar Hassan and Aram Kurd doused the shop in petrol before causing the blast.
David Herbert QC said Viktoria Ijevleva, 22, was left to die inside the shop, and the men would have known there were people in the flat above.
Mary Ragoobeer, 46, her teenage sons Shane and Sean, and Shanes girlfriend Leah Reek were killed in the explosion.
Ali, 37, Hassan, 33, and Kurd, 34, pleaded not guilty to five counts of murder and five alternative counts of manslaughter at a previous hearing.
Leicester Crown Court heard they destroyed the shop to gain a £300,000 insurance payout, which boils down to greed.
The explosion itself did not bother these defendants one bit, Mr Herbert said.
Addressing the jury on Wednesday, Mr Herbert said: At 7.01pm on the evening of February 25 2018, a massive explosion occurred in the basement of premises here in Leicester.
So massive that some in the neighbourhood thought it was a bomb that had exploded.
The explosion and the proceeding fire demolished a building and killed five people in the building – one person who was in the shop and four who were in the flat above enjoying a peaceful night in.
Jurors were shown CCTV footage of the blast from a number of angles.
Mr Herbert said: It was an explosion, the prosecution say, caused by many, many litres of petrol.
The explosion and the fire that followed was deliberately caused by these defendants who intended to profit from loss of stock, contents and future loss of business from the shop.
The evidence indicates that, had the crime been successful, the insurance payment would have been in the region of £300,000. It boils down to greed.
It was not an accident, the prosecution say, that the petrol used caused such devastating damage.
The court was told of the involvement of Ms Ijevleva in the alleged insurance scam.
Mr Herbert said: One of those who died, Viktorija Ijevleva, had assisted the defendants to obtain insurance.
The defendants thought she knew too much and decided to leave her to die in the explosion that they created.
In other words, the devastation that they caused was carried out with the intention to kill.
Ali, of Drake Close, Oldham, Hassan, of Eld Road, Coventry, and Kurd, of Hillary Place, Leicester, deny all 11 charges against them.
The trial continues.