Greek police said Sunday they have arrested three men of Pakistani origin for keeping seven people, including an Afghan family of four, whom they had helped cross into Greece, hostage and demanding money to release them. Police raids in two places outside the northern city of Thessaloniki on Friday freed the captives and led to the arrests of the traffickers, police said.

The Afghan family — the 66-year-old father, the 42-year-old mother and their two children, a boy and a girl, ages 14 and 16 — had crossed over from Turkey about a week ago. The traffickers kept them hostage, separating the parents from the children, and demanding 6,000 euros (USD 7,000) to release them, police said.

The traffickers had been in contact with an older son of the Afghan couple, who lives in the UK, for the transfer of money. It was he who tipped off the authorities. When police raided the place where the children were kept, they also found the three captive Pakistanis, whom they didn’t know about beforehand. The traffickers were demanding a ransom of 2,000 euros (USD 2,320) from their three compatriots.

Police also arrested two of the traffickers, ages 31 and 36. The third trafficker, a 19-year-old, was arrested when the parents were freed, police said.