Gardai believe they have busted a crime group that has been targeting sex workers in violent attacks across the country.
The gang is suspected of assaulting and robbing at least seven sex workers in recent weeks, but gardai fear the number is higher as some victims may not yet have come forward.
Four members of the gang, aged between 18 and 37, were arrested yesterday after gardai raided a house in Clonsilla, as well as two other properties in the west of the city.
The foreign nationals are being questioned over a wide range of offences including burglary, assault and robbery of sex workers in Dublin and the Midlands.
Sources said the gang, who have been in Ireland for only a short period, specialise in targeting workers who advertise their services online.
In each crime, an online appointment was made before the sex worker was robbed and in some cases subjected to a violent assault.
Male and female workers were targeted in what have been described as "extremely terrifying" ordeals.
An investigation was launched by the Garda Nation- al Protective Services Bureau (GNPSB) under Operation Quest when a number of attacks on sex workers in Dublin were reported last month.
More recently, a similar att-ack was reported in Roscommon. Following an extensive investigation, gardai from that division identified a suspected getaway vehicle used by the gang.
As a result, a number of searches were carried out in Dublin on Tuesday and led to four suspected members of the Romanian gang being arrested.
A fifth man was detained in relation to a warrant and was brought before the court.
"The men involved are linked to a Romanian crime gang who specialise in the targeting of sex workers," a source told the Herald.
"Due to their line of work, they may operate alone at times and that makes them vulnerable, and unfortunately these criminals exploit this.
"From initial inquiries, they appear to only have been in Ireland for some months, so gardai are liaising with other police forces to learn more about their background.
"As a result of excellent work from gardai at GNPSB and the Roscommon/Longford division, the suspects were identified and arrested."
Gardai are continuing to appeal to any sex worker who may have been subjected to a similar attack to report it.
Anyone who comes forward will be treated confidentially and with compassion and sensitivity, a spokeswoman said.
"An Garda Siochana is also appealing to any person with information on these callous, targeted attacks to contact gardai to assist in bringing these dangerous attackers to justice," she added.