An American man with Asperger’s syndrome, who took the internet by storm with a video of his dog comforting him, has been shot dead by police.

After officers were called to his flat in Arizona for a suicide call, transexual Kayden Clarke - previously known as Danielle Jacobs - reportedly tried to attack them with a knife.

Speaking to AZ Family, Detective Esteban Flores said the 24-year-old was transported to hospital to undergo surgery after officers shot him but died later that evening.

Talking to The Daily News, his mother, Stacia - who continued to refer to him as a woman - expressed shock at the death.

“I talked to her last night and the night before and she seemed fine," she said.

“Before the police arrived she wasn't posing a threat to the community at all. And the police came into her own place.

“They shot and killed a 24-year-old autistic, mentally ill individual whom they had been familiar with and were aware of her special needs.'

Danielle Jacobs: 'This is what having Asperger's is like'

Last year, Mr Clarke gained attention after posting a video in which he tries to punch himself and his Rottweiler comforts him.

“This is what having Asperger's like,” he wrote alongside the video.

Speaking to The Huffington Post before transitioning last year, he spoke candidly about his disability.

“When I have a meltdown, I often have self-injurious behaviour and I often self-harm," he said.

Although this video was later made private, Mr Clarke continued to post other videos of the dog consoling her up until three days before he died.

Speaking to AZ Family, Detective Esteban Flores from the Mesa Police Department in Arizona said the police had received multiple calls about a suicidal woman that day.

“She had one knife that we know of, she had something else we're not sure what it was, the officers said it was dark inside the room," he said.

“When she made contact with them she approached them with the knife, extended it out, and they felt threatened.”