A couple have been arrested on suspicion of holding a woman as a domestic slave in Belfast for more than six years.
Police said the arrests are the first of their kind in Northern Ireland .
The suspected victim escaped the property where she was allegedly being held around 16 months ago and alerted a member of the public, who contacted police.
An investigation has been running ever since and on Tuesday officers moved to arrest the two suspects.
A 33-year-old man was detained in east Belfast. A search was also carried out at a property and a number of documents and mobile phones were seized.
A 25-year-old woman was arrested in Scotland and is being taken back to Northern Ireland for questioning.
They are being held on suspicion of human trafficking offences for the purpose of domestic servitude.
The suspects are both from Africa, though from different countries.
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Police Service of Northern Ireland (PSNI) Detective Inspector Mark Bell, head of PSNI's Modern Slavery and Human Trafficking Unit, said: "This victim was brought to Northern Ireland and alleges this was going on for six years until it was brought to our attention.
"Thankfully this victim had the opportunity to leave their home address on this particular occasion and made contact with a member of the public, and thankfully that member of the public knew what the signs and indicators were to look out for and the police have then got involved."
Mr Bell said the investigation had been "protracted".
"It can be hard to believe that modern slavery and human trafficking exists today but it is all too real, especially for the victims," he said.
"Modern slavery is unacceptable as it violates human rights and denies victims their rights to life, freedom and safety. The criminals prey on vulnerable people, control them by fear and exploit them for their own selfish gains.
"These arrests are part of a protracted investigation into human trafficking for domestic servitude in Northern Ireland which has been going on for over a year. They are the first arrests of their kind.
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"Modern slavery is often an unseen crime as victims can be afraid to speak out or may be being held captive, and human trafficking for the purposes of domestic servitude can be particularly difficult to detect.
"Victims may be afraid to speak out so we need the public to be aware of the signs to look for so that they don't miss the opportunity to intervene in a modern slavery incident."
The detective said in the last 12 months his team had investigated 59 potential victims of modern slavery and human trafficking - a marked increase from 36 the previous financial year.
