"I sat there as a grieving mother praying for some sign of humility from them, praying for some sign of humanity from them, but instead they deepened our suffering."
Valbona Shekaj's son Klevi Shekaj, 23, was murdered along with 15-year-old Leo Reid while they were at a music video shoot in Archway, north London, in 2023.
On Friday, Lorik Lupqi, 22; Jason Furtado, 28; Abel Chunda, 29; Xavier Poponne, 22; and Eden Clark, 31, will be sentenced at the Old Bailey having been found guilty of double murder and attempted murder following a long-running trial.
During the sentencing hearing on Thursday, Leo's mother, Valentina Locci, said no sentence would be enough for the "callous, vicious, cold-blooded" killing of her "beautiful, charming intelligent" son.
Facing her son's killers in court, Ms Locci said: "Just for the fact that another human being can treat another human so poorly, careless, without any regard, only means that you must not be bothered by your conscience.
"My past, present and future has been crashed and taken, not only from me but my family, his siblings and all of our loved ones and friends, and for what?
"An adrenaline rush, an ego boost, a full sense of worth, a selfish gratification with no rewards, at cost to others. What I lost, what we have lost, cannot be found nor replaced."
She added: "I and all who loved Leo will live knowing of the brutality he suffered to his last breath."
Ms Shekaj said in her statement that her son was "extraordinary" - a "kind, bright soul full of possibilities".
In a statement read on her behalf by prosecutor Ben Lloyd, Ms Shekaj said she had felt "broken" by the defendants' behaviour during the trial.
"Instead of showing remorse or asking for forgiveness, they smirked at us from the defendant's box.
"I kept looking at them, hoping to see something, regret, sorrow, anything that showed they understood what they did.
"Instead, they smirked, they argued with their lawyers, complained about proceedings, acted like this was all some inconvenience for them.
"They played with our pain, and treated this entire trial as a game, as if the life they took and the devastation they caused meant nothing.
"I sat there as a grieving mother praying for some sign of humility from them, praying for some sign of humanity from them, but instead they deepened our suffering."
The court heard that aspiring cryptocurrency businessman Mr Shekaj's final words to his mother were a promise to be home in five minutes after going out to meet friends.
Instead, at 02:00, she answered the door to police officers with news that "no mother should ever have to hear", she said.
"As a single mother, Klevi was not just my son; he was my companion, my confidante and unwavering support," she said.
"He was thoughtful beyond his years, kind in ways both small and significant. He looked after me as much as I looked after him.
"The promise of who he was becoming, all his potential, was snuffed out in an act of senseless violence."
The men, who were described in court as "smirking" killers, ran amok at the music video shoot and fatally stabbed Klevi and Leo and severely injured Abdullah Abdullahi, 28, for an "adrenaline rush".
Lupqi and Furtado had planned the attack and enlisted the others to help, jurors were told.
On Thursday, Lupqi was double handcuffed in the dock over concerns of a violent outburst after he attacked Chunda, his co-accused, during the trial.
After hearing the victim impact statements, Lupqi was asked if he would like to say anything in mitigation for his crimes.
In response, the defendant, who was unrepresented by a lawyer, told Judge Anuja Dhir KC: "Suck your mother."
The judge warned Lupqi he would be sent out of court if there was a repeat of his bad behaviour.
Chunda's barrister Bernard Richmond KC acknowledged the defendants' behaviour in court had been "reprehensible" but argued it should have no impact on the sentences they receive.
However, Judge Dhir observed the defendants faced life sentences and that she could take account of any remorse - or lack of it - when deciding how long they should serve in prison before being eligible for parole.
She adjourned the hearing until 10:00 BST on Friday.