Robbers who raided the Casino di Venezia on Wednesday in a clock-work hold-up spoke Maltese and did not have foreign accents, staff and patrons have told the police.
Investigators suspect that the men were the same who unsuccessfully tried to force open a bank van exactly a month before in Sta Venera.
The casino hold-up is now believed to have involved six men: four entered the premises, one waited in the getaway car and another was in the boat alongside Fort St Angelo.
The men dumped their Pajero vehicle into the sea before dashing away in the boat, which has still not been traced.
The police said yesterday they had arrested a number of persons for questioning.
Among them was the security guard on duty at the entrance to the Vittoriosa waterfront on the evening of the hold-up. It is usually the practice for the security guard to ask those driving onto the quay for their details.
The investigators are also examining a wig and a scarf found inside the stolen Pajero. The clothing did not belong to the vehicle owner.