The lawyer for the man charged with the brutal murder of a Chasidic child in August has suggested that his client’s mental state was due to "inbreeding" in the strictly Orthodox community.

Levi Aron appeared in court in Brooklyn via a video link earlier this week. He is alleged to have killed Leiby Kletzky in July, in a case that sent shockwaves around the close-knit Chasidic community of New York.

The eight-year-old’s dismembered body parts were found in a suitcase and at Aron's home, and Aron later confessed to the crime.

Aron's lawyer Howard Greenberg, who is understood to be pursuing an insanity defence, said in court that his client may have a mental deficiency due to inbreeding amongst the Chasidic community.

The New York Post reported him saying: "everybody knows when blood relations have offspring, there can be genetic defects. It's something that needs to be investigated down to the ground."

Aron was declared competent to stand trial after a psychological exam, but Mr Greenberg has suggested at a previous court hearing that this should not stand. He said the confession his client signed soon after the murder was not valid, stating: "This guy would admit he shot Kennedy if you spent enough time with him."