The white speedboat used by robbers who raided the Casino di Venezia at the Vittoriosa waterfront last Wednesday has still not been found as police continue their investigations into the heist.

The robbery involved at least six men, four of whom entered the casino, while a fifth waited for them in a green Mitsubishi Pajero which had been stolen earlier in the week. The vehicle was driven to the far end of the waterfront, where a sixth man was waiting in a small white boat that was used to flee from the quay. The Pajero was dumped in the sea and recovered by police the following morning.

Sources said at least one of the robbers uttered words in Maltese while another two spoke in English, but their accent raised suspicion that they could be locals.

The hold-up, captured on closed-circuit television cameras inside and outside the casino and along the waterfront, lasted about three minutes. Sources said that although the police examined the footage, this was not of much help as the robbers had covered their faces.

Sources said the robbers must have planned the robbery carefully as they chose to commit the crime on Wednesday evening, a quiet day at the casino and also the night before money is collected by security guards.

The police have still not divulged the exact amount that was stolen, which has been revised several times since the hold-up. The figure is believed to be close to €500,000.

The investigators are believed to also be linking Wednesday's robbery to the foiled robbery on a security van in St Venera last month.

Three vans, a pickup truck, a motorcycle and a bulldozer blocked the path of security van carrying about €2.8 million but they failed to gain access to the cash.