A mother and her boyfriend have been found guilty of murdering her 15-year-old son who died after a campaign of torture.
Sebastian Kalinowski died of an infection caused by “untreated complications of multiple rib fractures”, after weeks of what prosecutors described as “cruel assaults and abuse” at the hands of his mother Agnieszka Kalinowska, 35, and her long-term partner Andrzej Latoszewski, 38.
A jury heard how Sebastian was beaten with a bed slat, whipped with an extension cable and stabbed with a needle by his mother and her partner.
After the couple were arrested in connection with Sebastian’s death, police seized CCTV cameras from their house in Huddersfield, West Yorkshire, which prosecutors said had been installed partly to “monitor and exert control over Sebastian remotely”.
Kalinowska and Latoszewski denied murdering Sebastian but were found guilty at Leeds Crown Court on Friday.
Kalinowska, wearing a grey T-shirt and a cross around her neck, sobbed loudly in the dock when the verdicts were delivered after the jury deliberated for around three and a half hours.
She continued crying uncontrollably as she was led from the dock.
Latoszewski showed no emotion as he stared at the floor.
The judge, Ms Justice Lambert, said the pair would not be sentenced until October at the earliest.
She praised the jury who had to watch the “horrifying” footage from the CCTV cameras multiple times during the trial.
The judge said: “You have had to endure quite horrifying footage of him suffering great pain over a long period of time.”
Prosecutor Jason Pitter QC told the jury during the trial: “The punishments, if that is an appropriate way to describe them, were by any stretch of the imagination cruel and became increasingly more severe and violent over time.
“It would appear that the punishments were precipitated by things such as Sebastian merely dropping food on his bedroom floor, or even just having gone to the toilet during the night.”
Jurors heard that from January 2021, “the disciplining of Sebastian became progressively harsh” and he was “kept deliberately out of the way of others, either as part of the system of punishment or to hide the abuse”.
Mr Pitter said emergency services were called to the defendants’ house by Latoszewski on 13 August 2021 “after Sebastian had been unconscious for some two and a half hours”.
The court heard that an examination of Sebastian revealed injuries including bruising to his buttocks, forehead, jaw, abdomen, arms and legs, and multiple rib fractures.
Mr Pitter said the defendants’ telephones and CCTV footage “document the catalogue of abuse that Sebastian had endured before his death”.
He said: “A broad description is one of Sebastian being attacked, principally and most severely by Latoszewski, but with his mother being involved at various times.
“It included messages and recordings of conversations which have the defendants speaking of and to Sebastian in the most derogatory and inhuman ways, in the context of a perceived need to punish him.
“That included forcing him to undertake physical and humiliating drills, even when he was too weak to really do so.”
Footage played to jurors included Latoszewski beating Sebastian’s buttocks with what, Mr Pitter said, appears to have been a slat from a bed.
Further clips included Latoszewski making Sebastian do exercises and whipping him with an extension cable to “spur him on”.
Mr Pitter said video from Latoszewski’s phone also contained clips of him “verbally abusing” a “visibly upset” Sebastian.
On the day before Sebastian’s death, Latoszewski was seen on the CCTV “forcing food and drink into Sebastian’s mouth” and “stabbing him a number of times” with a needle in the groin and thigh, “apparently laughing whilst he did so”.
The prosecutor added that Kalinowska at one point “took over stabbing Sebastian with the needle”.
Jurors heard that on the morning of Sebastian’s final day, he went through “the routine of being assaulted by both defendants”.
Mr Pitter said CCTV showed Latoszewski taking Sebastian out of the bedroom at 8.25am, before carrying him back around 15 minutes later, “naked, clearly wet and unconscious”.
Kalinowska told the jury she “should have died instead of him” and that she was “petrified and scared” of Latoszewski.
The jurors were told Sebastian had been in the UK for less than a year after moving from Poland to live with the defendants.
The court heard teaching staff describing him as “a pleasant and well-mannered boy” who “was observed to be quiet and timid, and at times appeared sad”.
Additional reporting by Press Association