AMSTERDAM (AP) — Dutch prosecutors have arrested eight people suspected of involvement in robbing or extorting money from tourists by forcing them to pay extreme prices for journeys from Amsterdam's Schiphol Airport into the popular Dutch city.

Prosecutors said Friday that one Swedish tourist was made to pay 595 euros ($630) for a ride into the city, which should cost around 40 euros ($43), and had his camera stolen. A Japanese tourist was locked in a taxi until he paid 300 euros ($318) for his ride into Amsterdam.

Four taxi drivers were among the suspects arrested. Prosecutors say the alleged ringleader was detained in a prison cell, where he was serving a sentence for another crime.

Prosecutors say police found a gun in one taxi during the investigation.