Four males were behind bars on Friday charged with blackmail as part of an ongoing investigation into the extortion syndicate that allegedly preyed on men who used hook-up apps including Grindr during the past three months.

ACT Policing launched an investigation into the alleged ruse after two men came forward to the AIDS Action Council in January.

The group had allegedly used the apps to set up meetings before they threatened and blackmailed victims, demanding up to $1000 cash.

The prosecution opposed bail when two boys aged 16 and a third boy, 15, faced the ACT Childrens' Court.

A fourth man, 18, who was the brother of one of the 16-year-olds, appeared in the ACT Magistrates Court.

None of the men have entered pleas.

Prosecutor Todd Trotter said police feared the teenagers would reoffend, threaten witnesses or tamper with evidence if released.

The first boy, 16, was charged with two blackmail offences, and possessing and cultivating cannabis.

Police allege the boy had posted a threatening message on one alleged victim's Facebook page and visited his house the night before the man died by suicide in January.

He didn't apply for bail through his Legal Aid duty lawyer.

The second boy, aged 15, was charged with blackmail and using a carriage service to menace, harass or offend.

Senior Constable Nathan Bakes told the court officers had seized clothing, sim cards, drugs and mobile phones that contained many text messages "with blackmail themes" when they raided a series of homes on Thursday.

He said many of those items were being examined by digital forensics officers for evidence and there were concerns some information could be stored in iCloud. Police expected more victims would come forward.

"We haven't established how many other members may be involved in this syndicate," he said.

He said the 15-year-old boy was aware of the alleged victim's death and had shown no remorse, refusing to answer the majority of questions police asked him in an interview.

The boy's lawyer, Sarah Boxall, was granted a request for his bail application to be adjourned.

A third boy, aged 16, faced two charges of blackmail. The court heard he'd made admissions to police but also had expressed no remorse.

His lawyer, Paul Edmonds, strongly objected to the alleged victim's suicide being mentioned on his client's court documents.

He said it was "grossly inappropriate" to mention such a serious allegation and bordered on "improper conduct" as the boy's alleged offences only appeared to be linked to the death by timing.

But the prosecution said the information was relevant and the reference in a bail opposition form linked the accused to the criminal group and not to the man's death.

First Constable Bec Wenham gave evidence police were still investigating how each of the group members were connected but said the accused was friends with another suspect on Facebook.

She said although the teenagers did not appear to be co-offenders, both operated with a "similar modus operandi".

The alleged gang members were difficult to track down because they had created fake profiles on at least two dating apps, First Constable Wenham said.

At least three other complainants had approached police but later refused to give statements for fear of social embarrassment once they found out they'd been communicating with minors.

"These victims have had a difficult few weeks.

"It's ruined some of their lives. I don't think these young people know how serious what they've done [is].

"It's very concerning; some of the victims have expressed suicidal thoughts."

The fourth alleged offender, an 18-year-old man, whose name has been suppressed, was charged with one blackmail offence.

His duty lawyer, Darryl Perkins, argued his client had a slightly lesser role in the scam and said his client was not connected to the alleged victim's death.

But Ms Hunter said: "This appears to be a gang scamming these unfortunate victims and the modus operandi appears to be similar."

She said it would be "catastrophic" if evidence in the case was lost or interfered with.

All four teenagers were remanded in custody. They will face court again next week.

Anyone with further information is urged to contact police on 131 444.

If you or someone you know needs help, contact beyondblue on 1300 22 4636, Lifeline on 13 11 44 or Kid's HelpLine on 1800 55 1800.