Two sisters of a Sydney murderer nearly caused his trial to collapse because they could not stop giggling as his police interview was played to a court.

Valnten and Valy Botrus were attending the NSW Supreme Court trial of their 20-year-old brother, Fredon, in September last year.

“Please stop laughing, it’s a very bad look,” solicitor Alen Sahinovic texted the pair while the court was still in session.

“We are in a murder trial.”

Botrus was ultimately found guilty of murdering 20-year-old Alfredo Isho as he sat getting a haircut at Bossley Park’s Classico Hair Salon in January, 2019.

The details of the incident and how close it came to derailing the proceedings were revealed in a judgment published yesterday.

The court was told Mr Sahinovic had unsuccessfully tried to subtly signal to the sisters that their laughter was inappropriate.

At least half of the jurors were observed to have noticed the giggling, which was triggered by Botrus’s on-screen swearing and discussions with police about a motorcycle he rode.

Two or three jurors reacted with a look of “clear disgust”, Mr Sahinovic noted.

CCTV footage of Alfredo Isho (upper right) moments after he was stabbed in the chest while having his hair cut. Photo: Supplied/NSW Police

One of the sisters later replied to Mr Sahinovic’s texts to apologise.

“That was a disaster,” he wrote back.

“The jury saw you guys repeatedly laughing throughout the interview.”

The following day, Botrus’s defence team made an application to discharge the entire jury, which the Crown opposed.

Botrus’s lawyers argued the jury could infer that his family considered the case a joke and that he did not take murder seriously, which had the potential to “irredeemably” prejudice the offender.

But Justice Michael Walton dismissed the application and said the jury had been attentive, engaged and compliant with their duties.

“Any reaction by the jury to the conduct of the sisters more widely reflects, in my view, an objection in being distracted in any way from their function,” he said.

After the incident, Botrus’s lawyers visited him in his cell and he tearfully told them: “That’s why I told them not to come.”

The jurors were also given a direction to put any observations of the courtroom out of their minds, because it formed no part of the evidence.

Botrus was yesterday handed a minimum 14-year jail sentence and a maximum term of 20 years behind bars for the killing, which the judge accepted was a “brazen, senseless and cowardly attack on an unsuspected victim”.

He will be eligible for parole in 2033.

–ABC