A mum is facing life behind bars after shooting her six-year-old son – whom she had just won custody over – in the head, leaving brain matter in her hair.

Julissa Angelica Genrich Thaler was originally charged with second-degree murder after traffic police in Orono, Minnesota, USA pulled her over for driving with a missing tyre and discovered the body of tragic Eli Hart in the boot alongside a shotgun.

Officers said there was blood on Thaler’s hands and what looked like a bullet hole in the back seat.

Eli had apparently been blasted multiple times.

Chillingly, prosecutors later detailed: “Officers arrested Defendant and observed that Defendant had blood and what appeared to be brain matter in her hair at the time of her arrest.”

Investigators went on to find “multiple locations where blood and brain matter were discarded”.

A post-mortem examination ruled that Eli had received as many as nine gunshot wounds in the head and torso.

The killing happened in May 2022, shortly after Eli’s parents waged a bitter battle for custody over him.

A judge in Dakota County had granted Thaler full custody over Eli shortly before the fatal shooting.

During the battle, dad Tony Hart had argued to the judge that Thaler posed a risk to his son.

He told local media: “I told him that she was displaying paranoia and auditory hallucinations. I said I feared for Eli’s safety. It all fell on deaf ears.”

Thaler, 28, is currently locked up in Hennepin County Jail on remand.

And local media have now revealed that prosecutors have charged her with first-degree murder in addition to her second-degree murder charge.

If convicted of the former, she faces life in prison.

Her next court hearing is scheduled for 20th January.