Anmol Chana was on trial at Birmingham Crown Court over the deaths of his mother Jasbir Kaur and her husband Rupinder Bassan.
The 26-year-old had claimed he acted in self-defence following a heated row at their home in Moat Road, Oldbury, on February 22, over abuse the defendant allegedly faced as a child.
Chana claimed Mr Bassan had approached him with a knife and threatened him. The defendant disarmed his stepfather, picked up the blade and used it to stab the couple multiple times – with his mother caught in between, trying to separate them both.
The couple, who had had been together for three years before marrying in 2019, had suffered "in excess" of more than 20 stab injuries each.
The court heard from Mr Jason Pitter QC, prosecuting, how Mrs Kaur had "in excess of 20 stab injuries to her front, back and to her hands where she was trying, we allege, to defend herself – the wounds cutting into bone".
Mr Bassan also had more than 20 injuries, including “one penetrating bone and the heart, sufficient to kill, one right through his arm, and a gaping injury to his neck, cutting the carotid artery and jugular vein, bisecting the spine”, Mr Pitter added.
After the stabbings the defendant claimed he "wasn't thinking straight" and "couldn't cope" with what had "just happened" and then moved the bodies to the backroom.
He wiped the blood off a door and then took money from her purse – totalling around £50, he said as he gave evidence to the court.
Asked by defence barrister Mr Gurdeep Garcha QC how he felt stealing from his mother’s purse while she was lying dead downstairs, he said: "I was feeling terrible."
The court heard Chana did not leave the address until about 1.30am on the Sunday, when he drove off in Mr Bassan’s yellow Toyota Aygo.
The defendant also took the knife with him because he was "feeling dazed", he said. Police and ambulance services did not attend the address until Tuesday morning, the court heard.
The court was told Chana drove straight home where he called the NHS helpline because his back was hurting after wrestling with Mr Bassan. He then called a number saved on his phone as "Brazil" – which was an escort – to "get some company", Chana said.
The defendant met up with the escort and went to the pub, had a drink, and calmly played pool in the aftermath of the attack.
After being arrested at his home in Hamilton Road, Chana denied any part in the killings during interview, telling officers "only God will judge".
He is also alleged to have plotted to flee the UK, booking a plane ticket to Italy via Turkey, and writing himself a reminder list including entries to "rob a Lidl" and "buy a new knife".
The jury at Birmingham Crown Court, after deliberating for around three hours, found Chana guilty on both charges of murder – with the verdict being unanimous.
Chana, who had pleaded not guilty and has been on trial since August 11, will be sentenced tomorrow at the same court.
'I am sad that their lives were ended'
The couple’s daughter, in a tribute, said: "My parents were the most loving people I’ve ever known. My mum went through hell and kept going to look after me and my brother. She’s the toughest woman I know. My dad was the perfect match for her. He was that person who was able to give my mum the space and warmth to relax and be loved in the way we all deserve.
"I am sad that their lives were ended so quickly without a second thought by a person whom they both loved dearly. Their lives together had just started. Not only did he take their lives, but he has tried to defame them in court to protect himself. I am angry at him for trying to use such tactics against their memory and against the person who always did her best for us.
"I have painful daily reminders that I won’t have their guidance through my adult life. The only comfort I have from any of this is that at least my parents are at peace together. Two beautiful souls eternally together. And that I’ll always love them."
Detectives from West Midlands Police have branded the crime as "despicable" as they released footage showing Chana's arrest.
Detective Inspector Hannah Whitehouse, from our homicide team, said: "Chana carried out a despicable crime against his family in their own home which should have been a place of safety.
"Our investigation revealed that Chana was fanatical about knives and had previously expressed a desire to kill his mother.
"Sadly we do not know what led him to carry out such a vicious and sickening attack.
"My thoughts remain with the couple’s wider family and friends. I can’t imagine how they are feeling; the shock and pain that his actions have caused will stay with them forever.
"I hope the guilty verdict today provides them with some comfort.
"Knife crime is devastating and this case has been a harsh reminder of the tragic consequences."