A son accused of killing and butchering his mother before throwing her body parts out of a car window along a highway has been seized by US police.

Suspect Troy Michael Mitteness, 56, from Burnsville, in the US state of Minnesota, confessed to stabbing his 82-year-old mother to death as she slept in June last year.

The police said that he had searched online for ‘how to kill an elderly person without poison’.

Investigators believe he killed mum Sandra Viola Mitteness after she found out he had been stealing money from her.

Following the murder he hacked her body into pieces and scattered by throwing them out the window while driving down the highway.

Mitteness, who was already being held for mail theft, theft and cheque forgery, admitted the gruesome killing under police questioning.

Dakota County Attorney Kathy Keena told local media: “The facts alleged in this case make it one of the most horrific and disturbing cases I’ve experienced in the course of my 34-year career.

“I wish to thank the Burnsville Police Department for their doggedness into the investigation of the disappearance of Ms Mitteness without which this case may have gone unsolved.”

She added: “My deepest sympathy is extended to the other family members and friends of Ms Mitteness for their great loss.”

Mitteness – it emerged – had been plundering his mother’s bank accounts and savings until she was almost penniless.

And when she began to demand an inspection of her accounts her son, he confessed, hatched a grim plot to kill her.

Mitteness told relatives and neighbours his mother had died last year when she fell down the stairs after a bout of COVID.

But when police checked his story they could find no contact with the funeral directors who were supposed to have buried her.

And when they checked back on a family car sold by Mitteness they found blood stains in the boot.

Then when investigators searched Mitteness’s home, they found a mattress covered in blood.

Killer Mitteness finally confessed that he had murdered his mother after spending “all of her money”.

During his online searches, he also looked up “the best spots to stab someone to make their death quick and painless”, according to local media.

Records from the Dakota County Sheriff’s Office show that Mitteness has been charged with second-degree murder and is in jail awaiting a court hearing.