Virginia Giuffre's relatives have thanked King Charles for backing abuse victims and "standing behind his people" after Andrew Mountbatten-Windsor's arrest.
Thames Valley Police detained the former prince on Thursday on suspicion of misconduct in public office before releasing him under investigation.
The King then said "the law must take its course" as he pledged his "full and wholehearted support and co-operation" to police.
Sky Roberts, Ms Giuffre's brother, has now said: "I will continue to commend the King for the actions that he's taken."
Mr Roberts added: "We have yet to see that from our own Government here."
He described the arrest as "a win" for his late sister and other survivors, calling it "a very good start to opening an investigation".
"To hear the King come out and acknowledge the fact that there needs to be an investigation, the law should be followed, like it should be followed for anybody that should be held to this type of investigation.
"And if it is found that he indeed did share secret information from his own Government... We would ask that he holds them to the highest extent of the law, even though it is his brother.
"I commend the King. I say thank you to the King and to the Royal Family for standing behind survivors, but also just standing behind their people to say, it doesn’t matter if you… it doesn't matter your wealth or your power, you don’t have a different set of laws for you that don’t apply to other people.
"And I think we’re seeing that in the UK right now."
Andrew has always denied any wrongdoing regarding Ms Giuffre | PA
Sky Roberts backed the King for supporting victims
| GETTYThe arrest on suspicion of misconduct in public office relates to Andrew's connections to paedophile financier Jeffrey Epstein.
Ms Giuffre, who took her own life last year, alleged Epstein trafficked her and forced her into sexual encounters with Andrew on three occasions.
One alleged incident occurred when she was 17 years old, while another took place during an orgy.
Andrew has consistently denied all allegations against him.
But King Charles has acted decisively, removing his younger brother's titles last year and backing the police probe on Thursday.
Amanda Roberts, Ms Giuffre's sister-in-law, appeared on BBC Newsnight to discuss the family's perspective.
She said: "There's still this underlying issue of survivors not getting their day in court and not seeing judicial, legal action."
ANDREW ARRESTED - READ MORE:
Ms Giuffre alleged Epstein trafficked her and forced her into sexual encounters with Andrew
|US DEPARTMENT OF JUSTICE
Ms Roberts described the arrest as a stepping stone toward broader accountability.
She said: "However, we still are true in believing that it is the breadcrumb to the larger dinner."
The family remains optimistic that this development will prompt deeper scrutiny of the sexual assault claims and trafficking allegations.
She said: "And so we are hopeful that this investigation now starts to open up that further probe into the sexual assault allegations, into the child trafficking. So it still is a win."
Ms Giuffre's family said they hoped the King's intervention is the 'breadcrumb to the larger dinner'
|GETTY
The news reached the family at 3am local time, triggering an intense emotional response.
Ms Roberts said: "It was 3am our time when we got the news and a bit of a shock, like, hits you in that moment and I think we celebrated in that moment and we were just like all struck."
She described the pain of being unable to share the moment with Virginia.
She said: "And if it had not been for Virginia, none of this would have been uncovered. None of this would have happened."
Andrew paid millions of pounds in 2022 to settle a civil sexual assault case with Ms Giuffre, despite claiming he never met her.
Her memoir, Nobody's Girl, was released posthumously last October.