Ghislaine Maxwell’s brother has said she is “looking pretty well, notwithstanding the conditions of detention”, after day three of her sex trafficking trial.

Kevin Maxwell spoke to reporters after the hearing in the Southern District of New York and reiterated that her treatement was the subject of a formal complaint to the United Nations.

Previous hearings have heard that guards repeatedly flashed light into the 59-year-old’s cell, which her lawyers said may have led to her suffering a black eye.

The court was previously told by Maxwell’s defence counsel that “she has grown increasingly reluctant to report information to the guards for fear of retaliation, discipline and punitive chores”.

Maxwell has been in custody since her arrest in July last year after Judge Alison J Nathan repeatedly denied requests for bail.

Another of the defendant’s brothers, Ian Maxwell, said his sister has been in “effective isolation” at the Metropolitan Detention Centre in Brooklyn, where she is being held in a 6ft by 9ft cell that has no natural light and has a toilet and a concrete bed.

He said Maxwell has been unable to sleep because she is watched around the clock by four guards and 10 cameras due to unwarranted concerns that she is a suicide risk.

Speaking outside court alongside Maxwell’s sister Isabel on Wednesday, Kevin Maxwell told reporters: “On a personal note it gave me a tremendous sense of relief to be close to her, to see her in the flesh, even to be able to speak with her.

“That’s the first time I’ve spoken to her personally for over 500 days since her pre-trial detention started.

“To see her looking pretty well, notwithstanding the conditions of detention, which are now the subject of a formal complaint to the United Nations committee on arbitrary detention.

“We respect the criminal justice system and process in this country and as a result we are not going to make any further comments while attending court and we won’t be answering any further questions – that’s out of respect for the process.”