A mum and her partner who murdered her 15-year-old son after subjecting him to a campaign of torture have been jailed for life with a minimum term of 39 years each.
Agnieszka Kalinowska and her long-term partner Andrzej Latoszewski had beaten Sebastian Kalinowski with a bed slat, whipped with an extension cable and stabbed him with a needle.
He eventually died of an infection caused by "untreated complications of multiple rib fractures" at his home in Huddersfield, West Yorkshire in August last year.
During sentencing the Mrs Justice Lambert called Latoszewsk a bully, adding: "Like all bullies, unable to maintain respect in another way you sought to intimidate Sebastian who was weaker than you and in Sebastian you found a way.
"CCTV footage shows you flying into a rage, pacing the room, with a grimace on your face as you scream at Sebastian."
She added that Sebastian's mum simply "did not care about him" and she was "only interested in herself".
The judge said in a letter Kalinowska wrote to Latoszewski she wrote about herself "and your continued love for him.
"You told him you would marry him. Your only real worry about what had happened to your cat after your arrest.
"In this very long letter there was not one word about your son Sebastian, his death and the loss of his life."
A jury at Leeds Crown Court earlier heard that after the couple were arrested in connection with Sebastian's death, police seized CCTV cameras from their house, which prosecutors said had been installed partly to "monitor and exert control over Sebastian remotely".
Kalinowska, 35 and Latoszewski, 38 had denied murdering Sebastian but were found guilty at Leeds Crown Court in July.
Jurors had previously been shown 'horrifying' CCTV footage from the couple's home, showing numerous incidents in which Sebastian was repeatedly punched, kicked and stamped on.
In one video, he was shown being whipped with a cable.
Jason Pitter QC, prosecuting, previously told the court Sebastian suffered "weeks, if not months of terrible, cruel, systematic assaults and ill treatment, neglect and abuse".
The court heard Sebastian had been in England for less than a year after moving from his home country of Poland, where he lived with his biological father.
His heartbroken dad watched the proceedings from Poland and branded them "ruthless monsters without an ounce of human feeling".
Sebastian's dad, Jacek Kalinowski, said his whole world came crashing down around him when he learned of his son's death.
He described his ex-wife, who listened to his words in the dock with tears in her eyes, as "the greatest evil that walks this world".
He continued: 'You are a truly cruel tyrant.'How can you be such ruthless monsters? Sebastian wished to make you love him.
"You reciprocated his love with pain. You are going to have to pay for every one of his tears."
In a statement read to the court Mr Kalinowski said: " You turned every day in his life into a nightmare and committed monstrosities that are truly mind-boggling.
"I will never comprehend how much hatred it takes to do such thing. The question is why? Why did you hate him to such a degree you let that psychopath treat him like that?
"How could you let your child be harmed? You took everything from him - his dignity and life."
He added: "The news of his death made part of me die with him. The wound you've inflicted will never heal and the pain will never go away.
"The knowledge his life was taken in such a brutal way is such a blow for me and my family. Nothing is ever going to be the same ever again and it is not the truth that time heals all wounds.
"Time has one purpose, and that is to accustom yourself to the pain."
Mr Kalinowski said the nightmare of his son's treatment "comes to haunt me every single day". He said he loved Sebastian but that he "could not protect him from evil - evil inflicted by his own mother."
Sebastian attended North Huddersfield Trust school, where he was described as a "model pupil", the court heard.
But his mother and step-father claimed he needed punishing for lying and playing truant from school.
During sentencing today the judge said footage on August 13 - the day of his death - shows Sebastian "moving like a very old man" before he is assaulted by his mother and dragged off by Latoszewski.
"When next seen on CCTV he is unconscious with no apparent signs of life." the judge said.
"By no later than 8.40pm it must have been obvious to you both Sebastian was either dead or dying.
"You Latoszewski gave chest compressions, you Kalinowska do nothing except go downstairs, check the curtain is closed, take a drink from a mug.
"At 9.26pm, the system is switched off and the cables ripped from the wall. You Latoszewski ring your work and say you had 'big problems.'
"You were both arrested."
The judge added: "Anyone has watched even part of the CCTV footage can only be utterly horrified by what they saw and bewildered why anyone would behave this way to a teenage boy.
"It begs the question why anyone would behave in this way - this is a question I have myself."
