Foday Musa looked broken as he listened to the last voice message he received from his son. It is 76 seconds long and the young man sounds desperate. He is crying, begging for his father's help.

It's so hard to hear. Hearing his voice hurts me, Musa told BBC Africa Eye, which was given exclusive access to a police unit that helped him as he searched for two of his children who had fallen victim to scammers.

It was in February 2024 that Musa's 22-year-old son and 18-year-old daughter, along with five others, were recruited from their remote village in the Faranah region of central Guinea by agents promising them work abroad.

The jobs never materialised and the so-called recruiters turned out to be human traffickers. The group was taken across the border into Sierra Leone and held captive.

My heart is broken. I can't stop crying. If you look at my eyes, you can see the pain, Musa said.

His case was picked up by the global policing agency Interpol in Guinea, which asked their unit in Sierra Leone to help. So last August Musa, travelled to Makeni, in central Sierra Leone, in a bid to find them.

Thousands of people across West Africa are being lured by a human trafficking scam, commonly known as QNET. Founded in Hong Kong, QNET itself is a legitimate wellness and lifestyle company - it allows people to sign up to buy their products and sell them online.

Its business model has faced criticism; however, in West Africa, criminal gangs are using its name as a front for illegal activities. The traffickers target people with the promise of work opportunities in places like the US, Canada, Dubai, and Europe, asking them to pay large sums of money for administration costs before they start the job.

Once they have paid, they are often trafficked to a neighbouring country and told they can only travel abroad once they recruit others into the scheme. Yet even when they bring in family and friends, the jobs never materialise.

Musa and his extended family had already given $25,000 (£19,000) to the traffickers - this encompassed the joining fees and extra money paid to try to get his children home. Travelling to Sierra Leone himself was his last hope.

Mahmoud Conteh, the head of investigations at the anti-trafficking unit of Interpol within the Sierra Leone police, said the case was a priority for his unit.

It's very easy for these traffickers to manoeuvre across each of our borders at these illegal crossing points, he told the BBC.

Following a tip-off that a large number of young people were being held in a location in Makeni, Musa joined the police as they raided the property, hoping to find his children. Bags and clothes were strewn across the floors. It is thought 10 to 15 people slept in each room. The Interpol team gathered everyone inside the property and found some as young as 14 had been living there.

Musa's children were not among them, though one young man said they had been there the previous week - the first potential sighting of his children in a year.

The group were transferred to the police station for screening before 19 of them were taken home to Guinea. The police have conducted more than 20 raids like this over the past year, rescuing hundreds of victims of human trafficking.

Musa never found his children and had no choice but to return to Guinea without them at the end of September. Conteh has since told the BBC that the traffickers released Foday's children not long afterwards. The BBC has confirmed that Musa's daughter made it back to Guinea, but she has not returned to her village - and did not want to be interviewed. The whereabouts of Musa's son remain unknown.

It remains a desperate situation for their father. After all that has happened, I really just want it all to be over and to see my kids, said Musa. We'd love them to come back to the village now - I'd love them to be here with me.\