All seven members of the gang, including two sisters, were arrested during raids in Madrid and the northeastern regions of La Rioja and Huesca, the Civil Guard police force said in a statement. They all belonged to the same Nicaraguan family.   

One of the ring leaders, a 48-year-old woman, was arrested at the capital's airport as she arrived with three “victims from Nicaragua who were going to be exploited,” the statement added.

Police suspect that 50 women were brought from Nicaragua to Spain since 2016 and forced to hand over virtually all of the money they earned by looking after the elderly or seriously ill.

Relatives of the gang in Nicaragua would recruit “mainly young women with little education”, by promising them well-paid jobs in Spain.   

Once they arrived, the gang would seize the women's passports and tell them that they owed €6,000  ($6,700) for travel which had to be quickly paid back.

The women were then forced to work in private homes providing care services to clients the gang found by placing ads online.   

They were also charged inflated prices by the gang for basic goods.   

“The criminal group dominated and controlled all of its victims with constant threats, intimidation, deceptions and coercion, warning them that their relatives in Nicaragua would suffer the consequences if they reported what was happening,” the police statement said.   

The gang was believed to have earned over 750,000 euros ($840,000) by exploiting the women.

The four women and three men who were arrested face charges of human trafficking for labour exploitation, belonging to a criminal organisation and money laundering.