Eleven people have been arrested in connection with the theft last year of two consignments of Apple iPhones with a combined value of €18.5m from Schiphol storage units, Schiphol police have said.

Six people have been arrested in one investigation, involving the theft of €3m worth of iPhones. A search of their homes in Zaandam, Amsterdam, Eindhoven and Haarlemmermeer turned up large quantities of cash, the police statement said.

In the investigation into the second theft, which accounted for the much bigger haul of €16m worth of phones, five people from Amsterdam, Purmerend, Hoofddorp and Zaandam were arrested.

Subsequent searches of business premises in Haarlemmermeer and Germany turned up 9,200 iPhones. Detectives also found several gold bars and €141,000 in cash at one of the suspect’s homes.

One of the suspects is thought to be involved in both robberies and the gang used falsified shipping papers and had inside help, a spokesman told broadcaster NOS.

Three of the suspects were employees of the distribution companies which stored the phones.

The investigations are continuing.