Man who killed backpackers Mia Ayliffe-Chung and Tom Jackson will not face trial.

A mentally ill Frenchman who fatally stabbed two other backpackers at a north Queensland hostel while under a delusion that people wanted to kill him won’t go to trial.

Smail Ayad dragged British backpacker Mia Ayliffe-Chung from her bed at the Home Hill hostel and stabbed her multiple times in August 2016.

The hostel manager tried to stop Ayad after the fatal attack, but was himself stabbed in the leg, the Brisbane Mental Health Court heard on Thursday.

Ayad jumped headfirst from the first floor balcony, sustaining neck and back fractures in the fall.

He then got up and stabbed the hostel owner’s dog.

“This was an extraordinary action and I think, in the context of all this offending, points to how frightened he was and how ill he was,” Justice Jean Dalton said on Thursday.

Ayad returned to the room where he had killed Ms Ayliffe-Chung and repeatedly stabbed British backpacker Tom Jackson as he tried to help the 20-year-old.

Justice Dalton discontinued criminal proceedings against Ayad after finding he was suffering paranoid schizophrenia at the time of the attack.

Ayad, who had smoked up to four joints a day for years before the attack, was under the delusion that 50 local farmers and hostel staff wanted to kill him and would burn his body in a pizza oven.

“He thought that a cleaner at the hostel had told him he would be killed when he went to check out and he thought the owner of the hostel was making excuses as to why he couldn’t leave,” Justice Dalton said.

“He interpreted her as telling him that he had to die.”

Mr Jackson’s father Les told the court he thought of his son at the beginning and end of each day.

“For me, sleepless and disturbed nights with visions of my defenceless son being attacked by a knife-wielding professional martial arts fighter or lying in a coma in a hospital bed are not uncommon,” he said.

Four psychiatrists have assessed Ayad, who was initially charged with a raft of offences including two counts of murder.

Criminal proceedings against him were dropped after the court hearing but he will be detained in a mental health facility.

The court heard he will likely be repatriated to France.