Detectives want to speak with potential victims or witnesses of abuse at a NSW juvenile justice centre and insist former inmates will be listened to "with an open mind".
Three former officers at the Airds detention centre in Sydney's southwest are facing historical child sex charges dating back to the mid-1990s.
But there could be more arrests to come.
Allegations regarding abuse by staff at the centre were first raised at the child abuse royal commission before being passed on to Campbelltown police.
Two women, aged 43 and 47, who were employed as psychologists at the centre were this month charged with historical sex offences.
The younger of the two faces 75 charges, including 21 sexual offences allegedly committed against a number of inmates aged 10 to 16 between 1997 to 2004.
The 47-year-old was charged with aggravated sexual assault and aggravated indecent assault offences that allegedly occurred between 2001 and 2004.
A third woman, also 43, was charged in May over alleged assaults in 1996 and 1997 when she too worked as a juvenile justice officer at the Airds detention centre.
Detectives spoke with between 50 and 60 people as part of their investigation - including dozens of former inmates, staff and friends of the victims.
Detective Chief Inspector Greg Inger says historical matters are often partially investigated if a complainant changes their mind about what they want to report.
"Allegations around this unfortunately come up every once in a while - sometimes there's enough to proceed to charge and sometimes there's not," he told AAP.
Mr Inger encourages anyone with information about abuse to contact authorities.
"We'll look at everything with an open mind and try to dig into it as much as we can," he said.
"It won't preclude us from taking a complaint from someone just because they may be incarcerated or they may have a certain history."
However, the passage of time can often challenge law enforcement agencies.
"The longer something takes to be reported, the more chance there is of evidence being lost or the less chance of corroborating things," Mr Inger said.
"In saying that, it's never too late to report something.
"We're seekers of the truth so we'll always track things down as far as we can."
Juvenile Justice NSW has pledged to cooperate with the ongoing police investigation and says allegations of abuse against former staff are taken "very seriously".
"Juvenile Justice has contemporary safeguards in place as part of employee screening," a spokesman said in a statement.
"These include working with children checks and extensive criminal records check as part of employee screening."
Strikeforce Redcliffe has been established to investigate allegations of sexual abuse by former juvenile justice officers at Airds.
